1
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Paul I. Field theoretic description of nonlinear electro-optical responses in centrosymmetric electronic systems. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:433001. [PMID: 39029502 DOI: 10.1088/1361-648x/ad65ac] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 07/19/2024] [Indexed: 07/21/2024]
Abstract
Motivated by the recent developments in terahertz spectroscopy using pump-probe setups to study correlated electronic materials, we review the field theoretical formalism to compute finite frequency nonlinear electro-optical responses in centrosymmetric systems starting from basic time dependent perturbation theory. We express the nonlinear current kernel as a sum of several causal response functions. These causal functions cannot be evaluated using perturbative field theory methods, since they are not contour ordered. Consequently, we associate each response function with a corresponding imaginary time ordered current correlation function, since the latter can be factorized using Wick's theorem. The mapping between the response functions and the correlation functions, suitably analytically continued to real frequencies, is proven exactly. We derive constraints satisfied by the nonlinear current kernel and we prove a generalizedf-sum rule for the nonlinear conductivity, all of which are consequences of particle number conservation. The constraints guarantee that the nonlinear static responses are free from spurious divergences. We apply the theory to compute the gauge invariant nonlinear conductivity of a system of noninteracting electrons in the presence of weak disorder. As special cases of this generalized nonlinear response, we discuss its third harmonic and its instantaneous terahertz Kerr signals. The formalism can be used to compute the nonlinear conductivity in symmetry broken phases of electronic systems such as superconductors, density waves and nematic states.
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Affiliation(s)
- I Paul
- Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Cité, CNRS, 75205 Paris, France
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2
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Yang F, Wu MW. Optical response of Higgs mode in superconductors at clean limit: formulation through Eilenberger equation and Ginzburg-Landau Lagrangian. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:425701. [PMID: 38986477 DOI: 10.1088/1361-648x/ad61ae] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 07/10/2024] [Indexed: 07/12/2024]
Abstract
Both macroscopic Ginzburg-Landau Lagrangian and microscopic gauge-invariant kinetic equation suggest a finite Higgs-mode generation in the second-order optical response of superconductors at clean limit, whereas the previous derivations through the path-integral approach and Eilenberger equation within the Matsubara formalism failed to give such generation. The crucial treatment leading to this controversy lies at an artificial scheme that whether the external optical frequency is taken as continuous variable or bosonic Matsubara frequency to handle the gap dynamics within the Matsubara formalism. To resolve this issue, we derive the effective action of the superconducting gap nearTcin the presence of the vector potential through the path-integral approach, to fill in the long missing gap of the microscopic derivation of the Ginzburg-Landau Lagrangian in superconductors. It is shown that only by taking optical frequency as continuous variable within the Matsubara formalism, can one achieve the fundamental Ginzburg-Landau Lagrangian, and in particular, the finite Ginzburg-Landau kinetic term leads to a finite Higgs-mode generation at clean limit. To further eliminate the confusion of the Matsubara frequency through a separate framework, we apply the Eilenberger equation within the Keldysh formalism, which is irrelevant to the Matsubara space. By calculating the gap dynamics in the second-order response, it is analytically proved that the involved optical frequency is a continuous variable rather than bosonic Matsubara frequency, causing a finite Higgs-mode generation at clean limit.
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Affiliation(s)
- F Yang
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, and CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - M W Wu
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, and CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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3
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Sekiguchi F, Narita H, Hirori H, Ono T, Kanemitsu Y. Anomalous behavior of critical current in a superconducting film triggered by DC plus terahertz current. Nat Commun 2024; 15:4435. [PMID: 38789464 PMCID: PMC11126563 DOI: 10.1038/s41467-024-48738-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
The critical current in a superconductor (SC) determines the performance of many SC devices, including SC diodes which have attracted recent attention. Hitherto, studies of SC diodes are limited in the DC-field measurements, and their performance under a high-frequency current remains unexplored. Here, we conduct the first investigation on the interaction between the DC and terahertz (THz) current in a SC artificial superlattice. We found that the DC critical current is sensitively modified by THz pulse excitations in a nontrivial manner. In particular, at low-frequency THz excitations below the SC gap, the critical current becomes sensitive to the THz-field polarization direction. Furthermore, we observed anomalous behavior in which a supercurrent flows with an amplitude larger than the modified critical current. Assuming that vortex depinning determines the critical current, we show that the THz-current-driven vortex dynamics reproduce the observed behavior. While the delicate nonreciprocity in the critical current is obscured by the THz pulse excitations, the interplay between the DC and THz current causes a non-monotonic SC/normal-state switching with current amplitude, which can pave a pathway to developing SC devices with novel functionalities.
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Affiliation(s)
- Fumiya Sekiguchi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan.
| | - Hideki Narita
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Hideki Hirori
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Teruo Ono
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Yoshihiko Kanemitsu
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan.
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4
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Kim MJ, Kovalev S, Udina M, Haenel R, Kim G, Puviani M, Cristiani G, Ilyakov I, de Oliveira TVAG, Ponomaryov A, Deinert JC, Logvenov G, Keimer B, Manske D, Benfatto L, Kaiser S. Tracing the dynamics of superconducting order via transient terahertz third-harmonic generation. SCIENCE ADVANCES 2024; 10:eadi7598. [PMID: 38489363 PMCID: PMC10942118 DOI: 10.1126/sciadv.adi7598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 02/11/2024] [Indexed: 03/17/2024]
Abstract
Ultrafast optical control of quantum systems is an emerging field of physics. In particular, the possibility of light-driven superconductivity has attracted much of attention. To identify nonequilibrium superconductivity, it is necessary to measure fingerprints of superconductivity on ultrafast timescales. Recently, nonlinear THz third-harmonic generation (THG) was shown to directly probe the collective degrees of freedoms of the superconducting condensate, including the Higgs mode. Here, we extend this idea to light-driven nonequilibrium states in superconducting La2-xSrxCuO4, establishing an optical pump-THz-THG drive protocol to access the transient superconducting order-parameter quench and recovering on few-picosecond timescales. We show in particular the ability of two-dimensional TH spectroscopy to disentangle the effects of optically excited quasiparticles from the pure order-parameter dynamics, which are unavoidably mixed in the pump-driven linear THz response. Benchmarking the gap dynamics to existing experiments shows the ability of driven THG spectroscopy to overcome these limitations in ordinary pump-probe protocols.
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Affiliation(s)
- Min-Jae Kim
- Institute of Solid State and Materials Physics, TUD Dresden University of Technology, 01069 Dresden, Germany
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- 4th Physics Institute and Research Center SCoPE, University of Stuttgart, 70569 Stuttgart, Germany
| | - Sergey Kovalev
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - Mattia Udina
- Department of Physics and ISC-CNR, “Sapienza” University of Rome, 00185 Rome, Italy
| | - Rafael Haenel
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- Department of Physics and Astronomy & Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Gideok Kim
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Matteo Puviani
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Georg Cristiani
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Igor Ilyakov
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | | | | | | | - Gennady Logvenov
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Bernhard Keimer
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Dirk Manske
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Lara Benfatto
- Department of Physics and ISC-CNR, “Sapienza” University of Rome, 00185 Rome, Italy
| | - Stefan Kaiser
- Institute of Solid State and Materials Physics, TUD Dresden University of Technology, 01069 Dresden, Germany
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- 4th Physics Institute and Research Center SCoPE, University of Stuttgart, 70569 Stuttgart, Germany
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5
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Gassner S, Weber CS, Claassen M. Light-induced switching between singlet and triplet superconducting states. Nat Commun 2024; 15:1776. [PMID: 38413590 PMCID: PMC10899631 DOI: 10.1038/s41467-024-45949-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 02/08/2024] [Indexed: 02/29/2024] Open
Abstract
While the search for topological triplet-pairing superconductivity has remained a challenge, recent developments in optically stabilizing metastable superconducting states suggest a new route to realizing this elusive phase. Here, we devise a testable theory of competing superconducting orders that permits ultrafast switching to an opposite-parity superconducting phase in centrosymmetric crystals with strong spin-orbit coupling. Using both microscopic and phenomenological models, we show that dynamical inversion symmetry breaking with a tailored light pulse can induce odd-parity (spin triplet) order parameter oscillations in a conventional even-parity (spin singlet) superconductor, which when driven strongly can send the system to a competing minimum in its free energy landscape. Our results provide new guiding principles for engineering unconventional electronic phases using light, suggesting a fundamentally non-equilibrium route toward realizing topological superconductivity.
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Affiliation(s)
- Steven Gassner
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Clara S Weber
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Institut für Theorie der Statistischen Physik, RWTH Aachen and JARA - Fundamentals of Future Information Technology, D-52056, Aachen, Germany
| | - Martin Claassen
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Yuan J, Shi L, Yue L, Li B, Wang Z, Xu S, Xu T, Wang Y, Gan Z, Chen F, Lin Z, Wang X, Jin K, Wang X, Luo J, Zhang S, Wu Q, Liu Q, Hu T, Li R, Zhou X, Wu D, Dong T, Wang N. Dynamical interplay between superconductivity and pseudogap in cuprates as revealed by terahertz third-harmonic generation spectroscopy. SCIENCE ADVANCES 2024; 10:eadg9211. [PMID: 38335284 PMCID: PMC10857425 DOI: 10.1126/sciadv.adg9211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 01/10/2024] [Indexed: 02/12/2024]
Abstract
We report on nonlinear terahertz third-harmonic generation (THG) measurements on YBa2Cu3O6+x thin films. Different from conventional superconductors, the THG signal starts to appear in the normal state, which is consistent with the crossover temperature T* of pseudogap over broad doping levels. Upon lowering the temperature, the THG signal shows an anomaly just below Tc in the optimally doped sample. Notably, we observe a beat pattern directly in the measured real-time waveform of the THG signal. We elaborate that the Higgs mode, which develops below Tc, couples to the mode already developed below T*, resulting in an energy level splitting. However, this coupling effect is not evident in underdoped samples. We explore different potential explanations for the observed phenomena. Our research offers valuable insight into the interplay between superconductivity and pseudogap.
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Affiliation(s)
- Jiayu Yuan
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Liyu Shi
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Li Yue
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Bohan Li
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Zixiao Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Shuxiang Xu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Tiequan Xu
- Applied Superconductivity Center and State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Yue Wang
- Applied Superconductivity Center and State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu, China
| | - Zizhao Gan
- Applied Superconductivity Center and State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu, China
| | - Fucong Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zefeng Lin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xu Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Kui Jin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xinbo Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jianlin Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Sijie Zhang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Qiong Wu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Qiaomei Liu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Tianchen Hu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Rongsheng Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Xinyu Zhou
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Dong Wu
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Tao Dong
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Nanlin Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- Collaborative Innovation Center of Quantum Matter, Beijing, China
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7
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Lorenzana J, Seibold G. Long-Lived Higgs Modes in Strongly Correlated Condensates. PHYSICAL REVIEW LETTERS 2024; 132:026501. [PMID: 38277611 DOI: 10.1103/physrevlett.132.026501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 12/02/2023] [Accepted: 12/14/2023] [Indexed: 01/28/2024]
Abstract
We investigate order parameter fluctuations in the Hubbard model within a time-dependent Gutzwiller approach. While in the weak coupling limit we find that the amplitude fluctuations are short-lived due to a degeneracy with the energy of the edge of the quasiparticle continua (and in agreement with Hartree-Fock+RPA theory), these are shifted below the edge upon increasing the interaction. Our calculations therefore predict undamped amplitude (Higgs) oscillations of the order parameter in strongly coupled superconductors, cold atomic fermion condensates, and strongly interacting charge- and spin-density wave systems. We propose an experimental realization for the detection of the spin-type Higgs mode in undoped cuprates and related materials where, due to the Dzyaloshinsky-Moriya interaction, it can couple to an out-of-plane ferromagnetic excitation that is visible via the Faraday effect.
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Affiliation(s)
- J Lorenzana
- ISC-CNR and Department of Physics, University of Rome "La Sapienza", Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - G Seibold
- Institut Für Physik, BTU Cottbus, PBox 101344, 03013 Cottbus, Germany
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8
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Young DJ, Chu A, Song EY, Barberena D, Wellnitz D, Niu Z, Schäfer VM, Lewis-Swan RJ, Rey AM, Thompson JK. Observing dynamical phases of BCS superconductors in a cavity QED simulator. Nature 2024; 625:679-684. [PMID: 38267683 DOI: 10.1038/s41586-023-06911-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 11/29/2023] [Indexed: 01/26/2024]
Abstract
In conventional Bardeen-Cooper-Schrieffer superconductors1, electrons with opposite momenta bind into Cooper pairs due to an attractive interaction mediated by phonons in the material. Although superconductivity naturally emerges at thermal equilibrium, it can also emerge out of equilibrium when the system parameters are abruptly changed2-8. The resulting out-of-equilibrium phases are predicted to occur in real materials and ultracold fermionic atoms, but not all have yet been directly observed. Here we realize an alternative way to generate the proposed dynamical phases using cavity quantum electrodynamics (QED). Our system encodes the presence or absence of a Cooper pair in a long-lived electronic transition in 88Sr atoms coupled to an optical cavity and represents interactions between electrons as photon-mediated interactions through the cavity9,10. To fully explore the phase diagram, we manipulate the ratio between the single-particle dispersion and the interactions after a quench and perform real-time tracking of the subsequent dynamics of the superconducting order parameter using nondestructive measurements. We observe regimes in which the order parameter decays to zero (phase I)3,4, assumes a non-equilibrium steady-state value (phase II)2,3 or exhibits persistent oscillations (phase III)2,3. This opens up exciting prospects for quantum simulation, including the potential to engineer unconventional superconductors and to probe beyond mean-field effects like the spectral form factor11,12, and for increasing the coherence time for quantum sensing.
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Affiliation(s)
- Dylan J Young
- JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO, USA
| | - Anjun Chu
- JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO, USA
| | - Eric Yilun Song
- JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO, USA
| | - Diego Barberena
- JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO, USA
| | - David Wellnitz
- JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO, USA
| | - Zhijing Niu
- JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO, USA
| | - Vera M Schäfer
- JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO, USA
- Max-Planck-Institut für Kernphysik, Heidelberg, Germany
| | - Robert J Lewis-Swan
- Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK, USA
- Center for Quantum Research and Technology, University of Oklahoma, Norman, OK, USA
| | - Ana Maria Rey
- JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO, USA.
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO, USA.
| | - James K Thompson
- JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO, USA.
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9
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Zhang S, Sun Z, Liu Q, Wang Z, Wu Q, Yue L, Xu S, Hu T, Li R, Zhou X, Yuan J, Gu G, Dong T, Wang N. Revealing the frequency-dependent oscillations in the nonlinear terahertz response induced by the Josephson current. Natl Sci Rev 2023; 10:nwad163. [PMID: 37818116 PMCID: PMC10561709 DOI: 10.1093/nsr/nwad163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/15/2023] [Accepted: 05/15/2023] [Indexed: 10/12/2023] Open
Abstract
Nonlinear responses of superconductors to intense terahertz radiation has been an active research frontier. Using terahertz pump-terahertz probe spectroscopy, we investigate the c-axis nonlinear optical response of a high-temperature superconducting cuprate. After excitation by a single-cycle terahertz pump pulse, the reflectivity of the probe pulse oscillates as the pump-probe delay is varied. Interestingly, the oscillatory central frequency scales linearly with the probe frequency, a fact widely overlooked in pump-probe experiments. By theoretically solving the nonlinear optical reflection problem on the interface, we show that our observation is well explained by the Josephson-type third-order nonlinear electrodynamics, together with the emission coefficient from inside the material into free space. The latter results in a strong enhancement of the emitted signal whose physical frequency is around the Josephson plasma edge. Our result offers a benchmark for and new insights into strong-field terahertz spectroscopy of related quantum materials.
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Affiliation(s)
- Sijie Zhang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Zhiyuan Sun
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
| | - Qiaomei Liu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Zixiao Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Qiong Wu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Li Yue
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Shuxiang Xu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Tianchen Hu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Rongsheng Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Xinyu Zhou
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Jiayu Yuan
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Genda Gu
- Condensed Matter Physics and Materials Science Department, Brookhaven National Lab, Upton, NY 11973, USA
| | - Tao Dong
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Nanlin Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Beijing Academy of Quantum Information Sciences, Beijing 100913, China
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10
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Barresi A, Boulet A, Wlazłowski G, Magierski P. Generation and decay of Higgs mode in a strongly interacting Fermi gas. Sci Rep 2023; 13:11285. [PMID: 37438452 DOI: 10.1038/s41598-023-38176-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 07/04/2023] [Indexed: 07/14/2023] Open
Abstract
We investigate the life cycle of the large amplitude Higgs mode in strongly interacting superfluid Fermi gas. Through numerical simulations with time-dependent density functional theory and the technique of the interaction quench, we verify the previous theoretical predictions on the mode's frequency. Next, we demonstrate that the mode is dynamically unstable against external perturbation and qualitatively examine the emerging state after the mode decays. The post-decay state is characterized by spatial fluctuations of the order parameter and density at scales comparable to the superfluid coherence length scale. We identify similarities with FFLO states, which become more prominent at higher dimensionalities and nonzero spin imbalances.
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Affiliation(s)
- Andrea Barresi
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662, Warsaw, Poland
| | - Antoine Boulet
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662, Warsaw, Poland
- ISMANS CESI, 44 Avenue Frédéric Auguste Bartholdi, 72000, Le Mans, France
| | - Gabriel Wlazłowski
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662, Warsaw, Poland.
- Department of Physics, University of Washington, Seattle, WA, 98195-1560, USA.
| | - Piotr Magierski
- Faculty of Physics, Warsaw University of Technology, Ulica Koszykowa 75, 00-662, Warsaw, Poland
- Department of Physics, University of Washington, Seattle, WA, 98195-1560, USA
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11
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Fano interference between collective modes in cuprate high-T c superconductors. Nat Commun 2023; 14:1343. [PMID: 36906577 PMCID: PMC10008591 DOI: 10.1038/s41467-023-36787-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 02/10/2023] [Indexed: 03/13/2023] Open
Abstract
Cuprate high-Tc superconductors are known for their intertwined interactions and the coexistence of competing orders. Uncovering experimental signatures of these interactions is often the first step in understanding their complex relations. A typical spectroscopic signature of the interaction between a discrete mode and a continuum of excitations is the Fano resonance/interference, characterized by the asymmetric light-scattering amplitude of the discrete mode as a function of the electromagnetic driving frequency. In this study, we report a new type of Fano resonance manifested by the nonlinear terahertz response of cuprate high-Tc superconductors, where we resolve both the amplitude and phase signatures of the Fano resonance. Our extensive hole-doping and magnetic field dependent investigation suggests that the Fano resonance may arise from an interplay between the superconducting fluctuations and the charge density wave fluctuations, prompting future studies to look more closely into their dynamical interactions.
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12
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Millon C, Houver S, Saraceno CJ. 400 kHz repetition rate THz-TDS with 24 mW of average power driven by a compact industrial Yb-laser. OPTICS EXPRESS 2023; 31:7922-7932. [PMID: 36859913 DOI: 10.1364/oe.476261] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 12/02/2022] [Indexed: 06/18/2023]
Abstract
We demonstrate a high average power terahertz time-domain spectroscopy (THZ-TDS) set-up based on optical rectification in the tilted-pulse front geometry in lithium niobate at room temperature, driven by a commercial, industrial femtosecond-laser operating with flexible repetition rate between 40 kHz - 400 kHz. The driving laser provides a pulse energy of 41 µJ for all repetition rates, at a pulse duration of 310 fs, allowing us to explore repetition rate dependent effects in our TDS. At the maximum repetition rate of 400 kHz, up to 16.5 W of average power are available to drive our THz source, resulting in a maximum of 24 mW of THz average power with a conversion efficiency of ∼ 0.15% and electric field strength of several tens of kV/cm. At the other available lower repetition rates, we show that the pulse strength and bandwidth of our TDS is unchanged, showing that the THz generation is not affected by thermal effects in this average power region of several tens of watts. The resulting combination of high electric field strength with flexible and high repetition rate is very attractive for spectroscopy, in particular since the system is driven by an industrial and compact laser without the need for external compressors or other specialized pulse manipulation.
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13
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Marino J, Eckstein M, Foster MS, Rey AM. Dynamical phase transitions in the collisionless pre-thermal states of isolated quantum systems: theory and experiments. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:116001. [PMID: 36075190 DOI: 10.1088/1361-6633/ac906c] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 09/08/2022] [Indexed: 06/15/2023]
Abstract
We overview the concept of dynamical phase transitions (DPTs) in isolated quantum systems quenched out of equilibrium. We focus on non-equilibrium transitions characterized by an order parameter, which features qualitatively distinct temporal behavior on the two sides of a certain dynamical critical point. DPTs are currently mostly understood as long-lived prethermal phenomena in a regime where inelastic collisions are incapable to thermalize the system. The latter enables the dynamics to substain phases that explicitly break detailed balance and therefore cannot be encompassed by traditional thermodynamics. Our presentation covers both cold atoms as well as condensed matter systems. We revisit a broad plethora of platforms exhibiting pre-thermal DPTs, which become theoretically tractable in a certain limit, such as for a large number of particles, large number of order parameter components, or large spatial dimension. The systems we explore include, among others, quantum magnets with collective interactions,ϕ4quantum field theories, and Fermi-Hubbard models. A section dedicated to experimental explorations of DPTs in condensed matter and AMO systems connects this large variety of theoretical models.
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Affiliation(s)
- Jamir Marino
- Institut für Physik, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany
| | - Martin Eckstein
- Department of Physics, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Matthew S Foster
- Department of Physics and Astronomy, Rice University, Houston, TX 77005, United States of America
- Rice Center for Quantum Materials, Rice University, Houston, TX 77005, United States of America
| | - Ana Maria Rey
- JILA, National Institute of Standards and Technology, and Department of Physics,University of Colorado, Boulder, CO 80309, United States of America
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO 80309, United States of America
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14
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Dong T, Zhang SJ, Wang NL. Recent Development of Ultrafast Optical Characterizations for Quantum Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2110068. [PMID: 35853841 DOI: 10.1002/adma.202110068] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 06/09/2022] [Indexed: 06/15/2023]
Abstract
The advent of intense ultrashort optical pulses spanning a frequency range from terahertz to the visible has opened a new era in the experimental investigation and manipulation of quantum materials. The generation of strong optical field in an ultrashort time scale enables the steering of quantum materials nonadiabatically, inducing novel phenomenon or creating new phases which may not have an equilibrium counterpart. Ultrafast time-resolved optical techniques have provided rich information and played an important role in characterization of the nonequilibrium and nonlinear properties of solid systems. Here, some of the recent progress of ultrafast optical techniques and their applications to the detection and manipulation of physical properties in selected quantum materials are reviewed. Specifically, the new development in the detection of the Higgs mode and photoinduced nonequilibrium response in the study of superconductors by time-resolved terahertz spectroscopy are discussed.
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Affiliation(s)
- Tao Dong
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Si-Jie Zhang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
| | - Nan-Lin Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
- Beijing Academy of Quantum Information Sciences, Beijing, 100913, China
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15
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UDINA MATTIA, Fiore J, Cea T, Castellani C, Seibold G, Benfatto L. THz non-linear optical response in cuprates: predominance of the BCS response over the Higgs mode. Faraday Discuss 2022; 237:168-185. [DOI: 10.1039/d2fd00016d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent experiments with strong THz fields in unconventional cuprates superconductors have clearly evidenced an increase of the non-linear optical response below the superconducting critical temperature Tc. As in the case...
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16
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Abstract
Advances over the past decade have presented new avenues to achieve control over material properties using intense pulses of electromagnetic radiation, with frequencies ranging from optical (approximately 1 PHz, or 1015 Hz) down to below 1 THz (1012 Hz). Some of these new developments have arisen from new experimental methods to drive and observe transient material properties, while others have emerged from new computational techniques that have made nonequilibrium dynamics more tractable to our understanding. One common issue with most attempts to realize control using electromagnetic pulses is the dissipation of energy, which in many cases poses a limit due to uncontrolled heating and has led to strong interest in using lower frequency and/or highly specific excitations to minimize this effect. Emergent developments in experimental tools using shaped X-ray pulses may in the future offer new possibilities for material control, provided that the issue of heat dissipation can be resolved for higher frequency light. The concept of using appropriately shaped pulses of light to control the properties of materials has a range of potential applications, and relies on an understanding of intricate couplings within the material.![]()
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Affiliation(s)
- Steven L Johnson
- Institute for Quantum Electronics, ETH Zürich, Auguste-Piccard-Hof 1, 8093 Zürich, Switzerland.
- SwissFEL, Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
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17
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Derendorf P, Müller MA, Eremin I. Signatures of Collective Modes in Fifth Harmonic Generation of BCS superconductor. Faraday Discuss 2022; 237:186-197. [DOI: 10.1039/d2fd00067a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent advances in the field of THz spectroscopy allow for controlled experiments to measure signatures of collective excitations in the conventional $s$-wave superconductor in the fifth harmonic generation current (FHG)....
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18
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Puviani M, Baum A, Ono S, Ando Y, Hackl R, Manske D. Calculation of an Enhanced A_{1g} Symmetry Mode Induced by Higgs Oscillations in the Raman Spectrum of High-Temperature Cuprate Superconductors. PHYSICAL REVIEW LETTERS 2021; 127:197001. [PMID: 34797154 DOI: 10.1103/physrevlett.127.197001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 05/20/2021] [Accepted: 09/30/2021] [Indexed: 06/13/2023]
Abstract
In superconductors the Anderson-Higgs mechanism allows for the existence of a collective amplitude (Higgs) mode which can couple to eV light mainly in a nonlinear Raman-like process. The experimental nonequilibrium results on isotropic superconductors have been explained going beyond the BCS theory including the Higgs mode. Furthermore, in anisotropic d-wave superconductors strong interaction effects with other modes are expected. Here we calculate the Raman contribution of the Higgs mode from a new perspective, including many-body Higgs oscillations effects and their consequences in conventional, spontaneous Raman spectroscopy. Our results suggest a significant contribution to the intensity of the A_{1g} symmetry Raman spectrum in d-wave superconductors. In order to test our theory, we predict the presence of measurable characteristic oscillations in THz quench-optical probe time-dependent reflectivity experiments.
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Affiliation(s)
- M Puviani
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - A Baum
- Walther Meissner Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany
| | - S Ono
- Central Research Institute of Electric Power Industry, Yokosuka, 240-0196 Kanagawa, Japan
| | - Y Ando
- Institute of Physics II, University of Cologne, 50937 Köln, Germany
| | - R Hackl
- Walther Meissner Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany
| | - D Manske
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
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19
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Yamamoto K, Nakagawa M, Tsuji N, Ueda M, Kawakami N. Collective Excitations and Nonequilibrium Phase Transition in Dissipative Fermionic Superfluids. PHYSICAL REVIEW LETTERS 2021; 127:055301. [PMID: 34397242 DOI: 10.1103/physrevlett.127.055301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
We predict a new mechanism to induce collective excitations and a nonequilibrium phase transition of fermionic superfluids via a sudden switch on of two-body loss, for which we extend the BCS theory to fully incorporate a change in particle number. We find that a sudden switch on of dissipation induces an amplitude oscillation of the superfluid order parameter accompanied by a chirped phase rotation as a consequence of particle loss. We demonstrate that when dissipation is introduced to one of the two superfluids coupled via a Josephson junction, it gives rise to a nonequilibrium dynamical phase transition characterized by the vanishing dc Josephson current. The dissipation-induced collective modes and nonequilibrium phase transition can be realized with ultracold fermionic atoms subject to inelastic collisions.
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Affiliation(s)
- Kazuki Yamamoto
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Masaya Nakagawa
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
| | - Naoto Tsuji
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - Masahito Ueda
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
- Institute for Physics of Intelligence, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
| | - Norio Kawakami
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
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20
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Zhang X, Foster MS. Dissipative Hot-Spot-Enabled Shock and Bounce Dynamics via Terahertz Quantum Quenches in Helical Edge States. PHYSICAL REVIEW LETTERS 2021; 127:026801. [PMID: 34296892 DOI: 10.1103/physrevlett.127.026801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 04/22/2021] [Accepted: 06/09/2021] [Indexed: 06/13/2023]
Abstract
We study quantum quenches of helical liquids with spin-flip inelastic scattering. Counterpropagating charge packets in helical edges can be created by an ultrashort electric pulse applied across a 2D topological insulator. Localized "hot spots" that form due to scattering enable two types of strongly nonlinear wave dynamics. First, propagating packets develop self-focusing shock fronts. Second, colliding packets with opposite charge can exhibit near-perfect retroreflection, despite strong dissipation. This leads to frequency doubling that could be detected experimentally from emitted terahertz radiation.
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Affiliation(s)
- Xinghai Zhang
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Matthew S Foster
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
- Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
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21
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Maklar J, Windsor YW, Nicholson CW, Puppin M, Walmsley P, Esposito V, Porer M, Rittmann J, Leuenberger D, Kubli M, Savoini M, Abreu E, Johnson SL, Beaud P, Ingold G, Staub U, Fisher IR, Ernstorfer R, Wolf M, Rettig L. Nonequilibrium charge-density-wave order beyond the thermal limit. Nat Commun 2021; 12:2499. [PMID: 33941788 PMCID: PMC8093280 DOI: 10.1038/s41467-021-22778-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/26/2021] [Indexed: 12/02/2022] Open
Abstract
The interaction of many-body systems with intense light pulses may lead to novel emergent phenomena far from equilibrium. Recent discoveries, such as the optical enhancement of the critical temperature in certain superconductors and the photo-stabilization of hidden phases, have turned this field into an important research frontier. Here, we demonstrate nonthermal charge-density-wave (CDW) order at electronic temperatures far greater than the thermodynamic transition temperature. Using time- and angle-resolved photoemission spectroscopy and time-resolved X-ray diffraction, we investigate the electronic and structural order parameters of an ultrafast photoinduced CDW-to-metal transition. Tracking the dynamical CDW recovery as a function of electronic temperature reveals a behaviour markedly different from equilibrium, which we attribute to the suppression of lattice fluctuations in the transient nonthermal phonon distribution. A complete description of the system's coherent and incoherent order-parameter dynamics is given by a time-dependent Ginzburg-Landau framework, providing access to the transient potential energy surfaces.
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Affiliation(s)
- J Maklar
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany.
| | - Y W Windsor
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
| | - C W Nicholson
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
- Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Fribourg, Switzerland
| | - M Puppin
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
- Laboratory of Ultrafast Spectroscopy, ISIC, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - P Walmsley
- Geballe Laboratory for Advanced Materials and Department of Applied Physics, Stanford University, Stanford, CA, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - V Esposito
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - M Porer
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - J Rittmann
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - D Leuenberger
- Department of Physics, University of Zürich, Zürich, Switzerland
| | - M Kubli
- Institute for Quantum Electronics, Physics Department, ETH Zürich, Zürich, Switzerland
| | - M Savoini
- Institute for Quantum Electronics, Physics Department, ETH Zürich, Zürich, Switzerland
| | - E Abreu
- Institute for Quantum Electronics, Physics Department, ETH Zürich, Zürich, Switzerland
| | - S L Johnson
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
- Institute for Quantum Electronics, Physics Department, ETH Zürich, Zürich, Switzerland
| | - P Beaud
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - G Ingold
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - U Staub
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - I R Fisher
- Geballe Laboratory for Advanced Materials and Department of Applied Physics, Stanford University, Stanford, CA, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - R Ernstorfer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
| | - M Wolf
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany
| | - L Rettig
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany.
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22
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Lewis-Swan RJ, Barberena D, Cline JRK, Young DJ, Thompson JK, Rey AM. Cavity-QED Quantum Simulator of Dynamical Phases of a Bardeen-Cooper-Schrieffer Superconductor. PHYSICAL REVIEW LETTERS 2021; 126:173601. [PMID: 33988424 DOI: 10.1103/physrevlett.126.173601] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 03/22/2021] [Indexed: 05/12/2023]
Abstract
We propose to simulate dynamical phases of a BCS superconductor using an ensemble of cold atoms trapped in an optical cavity. Effective Cooper pairs are encoded via the internal states of the atoms, and attractive interactions are realized via the exchange of virtual photons between atoms coupled to a common cavity mode. Control of the interaction strength combined with a tunable dispersion relation of the effective Cooper pairs allows exploration of the full dynamical phase diagram of the BCS model as a function of system parameters and the prepared initial state. Our proposal paves the way for the study of the nonequilibrium features of quantum magnetism and superconductivity by harnessing atom-light interactions in cold atomic gases.
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Affiliation(s)
- Robert J Lewis-Swan
- Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, Norman, Oklahoma 73019, USA
- Center for Quantum Research and Technology, The University of Oklahoma, Norman, Oklahoma 73019, USA
- JILA, NIST, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
| | - Diego Barberena
- JILA, NIST, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
| | - Julia R K Cline
- JILA, NIST, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Dylan J Young
- JILA, NIST, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - James K Thompson
- JILA, NIST, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Ana Maria Rey
- JILA, NIST, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
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23
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Davis B, Saule T, Trallero-Herrero CA. Asymmetric high energy dual optical parametric amplifier for parametric processes and waveform synthesis. OPTICS EXPRESS 2021; 29:7379-7388. [PMID: 33726239 DOI: 10.1364/oe.417068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 02/12/2021] [Indexed: 06/12/2023]
Abstract
We report on an asymmetric high energy dual optical parametric amplifier (OPA) which is capable of having either the idlers, signals, or depleted pumps, relatively phase locked at commensurate or incommensurate wavelengths. Idlers and signals can be locked on the order of 200 mrad rms or better, corresponding to a 212 as jitter at λ=2 µm. The high energy arm of the OPA outputs a combined 3.5 mJ of signal and idler, while the low energy arm outputs 1.5 mJ, with the entire system being pumped with a 1 kHz, 18 mJ Ti:Sapphire laser. Both arms are independently tunable from 1080 nm-2600 nm. The combination of relative phase locking, high output power and peak intensity, and large tunability makes our OPA an ideal tool for use in difference frequency generation (DFG) in the strong pump regime, and for high peak field waveform synthesis in the near-infrared. To demonstrate this ability we generate terahertz radiation through two color waveform synthesis in air plasma and show the influence of the relative phase on the generated terahertz intensity. The ability to phase lock multiple incommensurate wavelengths at high energies opens the door to a multitude of possibilities of strong pump DFG and waveform synthesis.
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24
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Isgandarov E, Ropagnol X, Singh M, Ozaki T. Intense terahertz generation from photoconductive antennas. FRONTIERS OF OPTOELECTRONICS 2021; 14:64-93. [PMID: 36637784 PMCID: PMC9743868 DOI: 10.1007/s12200-020-1081-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/16/2020] [Indexed: 06/14/2023]
Abstract
In this paper, we review the past and recent works on generating intense terahertz (THz) pulses from photoconductive antennas (PCAs). We will focus on two types of large-aperture photoconductive antenna (LAPCA) that can generate high-intensity THz pulses (a) those with large-aperture dipoles and (b) those with interdigitated electrodes. We will first describe the principles of THz generation from PCAs. The critical parameters for improving the peak intensity of THz radiation from LAPCAs are summarized. We will then describe the saturation and limitation process of LAPCAs along with the advantages and disadvantages of working with wide-bandgap semiconductor substrates. Then, we will explain the evolution of LAPCA with interdigitated electrodes, which allows one to reduce the photoconductive gap size, and thus obtain higher bias fields while applying lower voltages. We will also describe recent achievements in intense THz pulses generated by interdigitated LAPCAs based on wide-bandgap semiconductors driven by amplified lasers. Finally, we will discuss the future perspectives of THz pulse generation using LAPCAs.
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Affiliation(s)
- Elchin Isgandarov
- Institut National de la Recherche Scientifique, Centre Énergie, Matériaux Télécommunications (INRS-EMT), Varennes, Québec, J3X 1S2, Canada
| | - Xavier Ropagnol
- Institut National de la Recherche Scientifique, Centre Énergie, Matériaux Télécommunications (INRS-EMT), Varennes, Québec, J3X 1S2, Canada
- Département de Génie Électrique, École de Technologie Supérieure (ETS), Montréal, Québec, H3C 1K3, Canada
| | - Mangaljit Singh
- Institut National de la Recherche Scientifique, Centre Énergie, Matériaux Télécommunications (INRS-EMT), Varennes, Québec, J3X 1S2, Canada
| | - Tsuneyuki Ozaki
- Institut National de la Recherche Scientifique, Centre Énergie, Matériaux Télécommunications (INRS-EMT), Varennes, Québec, J3X 1S2, Canada.
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25
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Gabriele F, Udina M, Benfatto L. Non-linear Terahertz driving of plasma waves in layered cuprates. Nat Commun 2021; 12:752. [PMID: 33531492 PMCID: PMC7854596 DOI: 10.1038/s41467-021-21041-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 01/07/2021] [Indexed: 12/02/2022] Open
Abstract
The hallmark of superconductivity is the rigidity of the quantum-mechanical phase of electrons, responsible for superfluid behavior and Meissner effect. The strength of the phase stiffness is set by the Josephson coupling, which is strongly anisotropic in layered cuprates. So far, THz light pulses have been used to achieve non-linear control of the out-of-plane Josephson plasma mode, whose frequency lies in the THz range. However, the high-energy in-plane plasma mode has been considered insensitive to THz pumping. Here, we show that THz driving of both low-frequency and high-frequency plasma waves is possible via a general two-plasmon excitation mechanism. The anisotropy of the Josephson couplings leads to markedly different thermal effects for the out-of-plane and in-plane response, linking in both cases the emergence of non-linear photonics across Tc to the superfluid stiffness. Our results show that THz light pulses represent a preferential knob to selectively drive phase excitations in unconventional superconductors. Josephson coupling determines the superconducting phase stiffness and sets the energy scale of plasma waves. Here, the authors show that THz light can induce two-plasmon excitations of both out-of-plane and in-plane phase modes, leading however to markedly different resonant and thermal effects due to the strong anisotropy of the Josephson couplings.
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Affiliation(s)
- Francesco Gabriele
- Department of Physics and ISC-CNR, 'Sapienza' University of Rome, Rome, Italy
| | - Mattia Udina
- Department of Physics and ISC-CNR, 'Sapienza' University of Rome, Rome, Italy
| | - Lara Benfatto
- Department of Physics and ISC-CNR, 'Sapienza' University of Rome, Rome, Italy.
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26
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Costa AT, Gonçalves PAD, Basov DN, Koppens FHL, Mortensen NA, Peres NMR. Harnessing ultraconfined graphene plasmons to probe the electrodynamics of superconductors. Proc Natl Acad Sci U S A 2021; 118:e2012847118. [PMID: 33479179 PMCID: PMC7848587 DOI: 10.1073/pnas.2012847118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
We show that the Higgs mode of a superconductor, which is usually challenging to observe by far-field optics, can be made clearly visible using near-field optics by harnessing ultraconfined graphene plasmons. As near-field sources we investigate two examples: graphene plasmons and quantum emitters. In both cases the coupling to the Higgs mode is clearly visible. In the case of the graphene plasmons, the coupling is signaled by a clear anticrossing stemming from the interaction of graphene plasmons with the Higgs mode of the superconductor. In the case of the quantum emitters, the Higgs mode is observable through the Purcell effect. When combining the superconductor, graphene, and the quantum emitters, a number of experimental knobs become available for unveiling and studying the electrodynamics of superconductors.
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Affiliation(s)
- A T Costa
- International Iberian Nanotechnology Laboratory, 4715-330 Braga, Portugal
| | - P A D Gonçalves
- Center for Nano Optics, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - D N Basov
- Department of Physics, Columbia University, New York, NY 10027
| | - Frank H L Koppens
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA - Institució Catalana de Recera i Estudis Avançats, 08010 Barcelona, Spain
| | - N Asger Mortensen
- Center for Nano Optics, University of Southern Denmark, DK-5230 Odense M, Denmark;
- Danish Institute for Advanced Study, University of Southern Denmark, DK-5230 Odense M, Denmark
- Center for Nanostructured Graphene, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - N M R Peres
- International Iberian Nanotechnology Laboratory, 4715-330 Braga, Portugal;
- Centro de Física das Universidades do Minho e do Porto, Universidade do Minho, 4710-057 Braga, Portugal
- Departamento de Física, Universidade do Minho, 4710-057 Braga, Portugal
- QuantaLab, Universidade do Minho, 4710-057 Braga, Portugal
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27
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Vaswani C, Kang JH, Mootz M, Luo L, Yang X, Sundahl C, Cheng D, Huang C, Kim RHJ, Liu Z, Collantes YG, Hellstrom EE, Perakis IE, Eom CB, Wang J. Light quantum control of persisting Higgs modes in iron-based superconductors. Nat Commun 2021; 12:258. [PMID: 33431843 PMCID: PMC7801641 DOI: 10.1038/s41467-020-20350-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 11/30/2020] [Indexed: 11/28/2022] Open
Abstract
The Higgs mechanism, i.e., spontaneous symmetry breaking of the quantum vacuum, is a cross-disciplinary principle, universal for understanding dark energy, antimatter and quantum materials, from superconductivity to magnetism. Unlike one-band superconductors (SCs), a conceptually distinct Higgs amplitude mode can arise in multi-band, unconventional superconductors via strong interband Coulomb interaction, but is yet to be accessed. Here we discover such hybrid Higgs mode and demonstrate its quantum control by light in iron-based high-temperature SCs. Using terahertz (THz) two-pulse coherent spectroscopy, we observe a tunable amplitude mode coherent oscillation of the complex order parameter from coupled lower and upper bands. The nonlinear dependence of the hybrid Higgs mode on the THz driving fields is distinct from any known SC results: we observe a large reversible modulation of resonance strength, yet with a persisting mode frequency. Together with quantum kinetic modeling of a hybrid Higgs mechanism, distinct from charge-density fluctuations and without invoking phonons or disorder, our result provides compelling evidence for a light-controlled coupling between the electron and hole amplitude modes assisted by strong interband quantum entanglement. Such light-control of Higgs hybridization can be extended to probe many-body entanglement and hidden symmetries in other complex systems. A collective excitation called Higgs mode may arise in multi-band superconductors via strong interband interaction, but it is yet to be accessed. Here, the authors observe a tunable coherent amplitude oscillation of the order parameter in Ba(Fe1−xCox)2As2, suggesting appearance and control of the Higgs mode by light tuning interband interaction.
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Affiliation(s)
- C Vaswani
- Department of Physics and Astronomy, Iowa State University, and Ames Laboratory, Ames, IA, 50011, USA
| | - J H Kang
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - M Mootz
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL, 35294-1170, USA
| | - L Luo
- Department of Physics and Astronomy, Iowa State University, and Ames Laboratory, Ames, IA, 50011, USA
| | - X Yang
- Department of Physics and Astronomy, Iowa State University, and Ames Laboratory, Ames, IA, 50011, USA
| | - C Sundahl
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - D Cheng
- Department of Physics and Astronomy, Iowa State University, and Ames Laboratory, Ames, IA, 50011, USA
| | - C Huang
- Department of Physics and Astronomy, Iowa State University, and Ames Laboratory, Ames, IA, 50011, USA
| | - R H J Kim
- Department of Physics and Astronomy, Iowa State University, and Ames Laboratory, Ames, IA, 50011, USA
| | - Z Liu
- Department of Physics and Astronomy, Iowa State University, and Ames Laboratory, Ames, IA, 50011, USA
| | - Y G Collantes
- Applied Superconductivity Center, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA
| | - E E Hellstrom
- Applied Superconductivity Center, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA
| | - I E Perakis
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL, 35294-1170, USA
| | - C B Eom
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - J Wang
- Department of Physics and Astronomy, Iowa State University, and Ames Laboratory, Ames, IA, 50011, USA.
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28
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Observing the emergence of a quantum phase transition shell by shell. Nature 2020; 587:583-587. [PMID: 33239796 DOI: 10.1038/s41586-020-2936-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 09/03/2020] [Indexed: 11/09/2022]
Abstract
Many-body physics describes phenomena that cannot be understood by looking only at the constituents of a system1. Striking examples are broken symmetry, phase transitions and collective excitations2. To understand how such collective behaviour emerges as a system is gradually assembled from individual particles has been a goal in atomic, nuclear and solid-state physics for decades3-6. Here we observe the few-body precursor of a quantum phase transition from a normal to a superfluid phase. The transition is signalled by the softening of the mode associated with amplitude vibrations of the order parameter, usually referred to as a Higgs mode7. We achieve fine control over ultracold fermions confined to two-dimensional harmonic potentials and prepare closed-shell configurations of 2, 6 and 12 fermionic atoms in the ground state with high fidelity. Spectroscopy is then performed on our mesoscopic system while tuning the pair energy from zero to a value larger than the shell spacing. Using full atom counting statistics, we find the lowest resonance to consist of coherently excited pairs only. The distinct non-monotonic interaction dependence of this many-body excitation, combined with comparison with numerical calculations allows us to identify it as the precursor of the Higgs mode. Our atomic simulator provides a way to study the emergence of collective phenomena and the thermodynamic limit, particle by particle.
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29
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Kurkjian H, Tempere J, Klimin SN. Linear response of a superfluid Fermi gas inside its pair-breaking continuum. Sci Rep 2020; 10:11591. [PMID: 32665570 PMCID: PMC7360786 DOI: 10.1038/s41598-020-65371-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/20/2020] [Indexed: 11/09/2022] Open
Abstract
We study the signatures of the collective modes of a superfluid Fermi gas in its linear response functions for the order-parameter and density fluctuations in the Random Phase Approximation (RPA). We show that a resonance associated to the Popov-Andrianov (or sometimes "Higgs") mode is visible inside the pair-breaking continuum at all values of the wavevector q, not only in the (order-parameter) modulus-modulus response function but also in the modulus-density and density-density responses. At nonzero temperature, the resonance survives in the presence of thermally broken pairs even until the vicinity of the critical temperature Tc, and coexists with both the Anderson-Bogoliubov modes at temperatures comparable to the gap Δ and with the low-velocity phononic mode predicted by RPA near Tc. The existence of a Popov-Andrianov-"Higgs" resonance is thus a robust, generic feature of the high-energy phenomenology of pair-condensed Fermi gases, and should be accessible to state-of-the-art cold atom experiments.
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Affiliation(s)
- H Kurkjian
- TQC, Universiteit Antwerpen, Universiteitsplein 1, B-2610, Antwerp, Belgium.
| | - J Tempere
- TQC, Universiteit Antwerpen, Universiteitsplein 1, B-2610, Antwerp, Belgium
| | - S N Klimin
- TQC, Universiteit Antwerpen, Universiteitsplein 1, B-2610, Antwerp, Belgium
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30
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Aryshev A, Potylitsyn AP, Naumenko GA, Shevelev M, Shkitov D, Sukhikh LG, Terunuma N, Urakawa J. Observation of grating diffraction radiation at the KEK LUCX facility. Sci Rep 2020; 10:7589. [PMID: 32372064 PMCID: PMC7200665 DOI: 10.1038/s41598-020-63462-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 03/31/2020] [Indexed: 12/03/2022] Open
Abstract
The development of linac–based narrow–band THz sources with sub–picosecond, \documentclass[12pt]{minimal}
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\begin{document}$$\mu J$$\end{document}μJ-level radiation pulses is in demand from the scientific community. Intrinsically monochromatic emitters such as coherent Smith–Purcell radiation sources appear as natural candidates. However, the lack of broad spectral tunability continues to stimulate active research in this field. We hereby present the first experimental investigation of coherent grating diffraction radiation (GDR), for which comparable radiation intensity with central frequency fine–tuning in a much wider spectral range has been confirmed. Additionally, the approach allows for bandwidth selection at the same central frequency. The experimental validation of performance included the basic spectral, spatial and polarization properties. The discussion of the comparison between GDR intensity and other coherent radiation sources is also presented. These results further strengthen the foundation for the design of a tabletop wide–range tunable quasi–monochromatic or multi–colour radiation source in the GHz–THz frequency range.
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Affiliation(s)
- A Aryshev
- KEK: High Energy Accelerator Research Organization, 1-1 Oho, Ibaraki, 305-0801, Tsukuba, Japan.
| | - A P Potylitsyn
- Tomsk Polytechnic University, Lenin ave. 30, Tomsk, 634050, Russian Federation, Russia.
| | - G A Naumenko
- Tomsk Polytechnic University, Lenin ave. 30, Tomsk, 634050, Russian Federation, Russia
| | - M Shevelev
- Tomsk Polytechnic University, Lenin ave. 30, Tomsk, 634050, Russian Federation, Russia
| | - D Shkitov
- Tomsk Polytechnic University, Lenin ave. 30, Tomsk, 634050, Russian Federation, Russia
| | - L G Sukhikh
- Tomsk Polytechnic University, Lenin ave. 30, Tomsk, 634050, Russian Federation, Russia
| | - N Terunuma
- KEK: High Energy Accelerator Research Organization, 1-1 Oho, Ibaraki, 305-0801, Tsukuba, Japan
| | - J Urakawa
- KEK: High Energy Accelerator Research Organization, 1-1 Oho, Ibaraki, 305-0801, Tsukuba, Japan
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31
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Chu H, Kim MJ, Katsumi K, Kovalev S, Dawson RD, Schwarz L, Yoshikawa N, Kim G, Putzky D, Li ZZ, Raffy H, Germanskiy S, Deinert JC, Awari N, Ilyakov I, Green B, Chen M, Bawatna M, Cristiani G, Logvenov G, Gallais Y, Boris AV, Keimer B, Schnyder AP, Manske D, Gensch M, Wang Z, Shimano R, Kaiser S. Phase-resolved Higgs response in superconducting cuprates. Nat Commun 2020; 11:1793. [PMID: 32286291 PMCID: PMC7156672 DOI: 10.1038/s41467-020-15613-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 03/02/2020] [Indexed: 11/29/2022] Open
Abstract
In high-energy physics, the Higgs field couples to gauge bosons and fermions and gives mass to their elementary excitations. Experimentally, such couplings can be inferred from the decay product of the Higgs boson, i.e., the scalar (amplitude) excitation of the Higgs field. In superconductors, Cooper pairs bear a close analogy to the Higgs field. Interaction between the Cooper pairs and other degrees of freedom provides dissipation channels for the amplitude mode, which may reveal important information about the microscopic pairing mechanism. To this end, we investigate the Higgs (amplitude) mode of several cuprate thin films using phase-resolved terahertz third harmonic generation (THG). In addition to the heavily damped Higgs mode itself, we observe a universal jump in the phase of the driven Higgs oscillation as well as a non-vanishing THG above Tc. These findings indicate coupling of the Higgs mode to other collective modes and potentially a nonzero pairing amplitude above Tc. Interaction between Cooper pairs and other collective excitations may reveal important information about the pairing mechanism. Here, the authors observe a universal jump in the phase of the driven Higgs oscillations in cuprate thin films, indicating the presence of a coupled collective mode, as well as a nonvanishing Higgs-like response at high temperatures, suggesting a potential nonzero pairing amplitude above Tc.
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Affiliation(s)
- Hao Chu
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany.,4th Physics Institute, University of Stuttgart, 70569, Stuttgart, Germany.,Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Min-Jae Kim
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany.,4th Physics Institute, University of Stuttgart, 70569, Stuttgart, Germany
| | - Kota Katsumi
- Department of Physics, University of Tokyo, Hongo, Tokyo, 113-0033, Japan
| | - Sergey Kovalev
- Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany
| | - Robert David Dawson
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Lukas Schwarz
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Naotaka Yoshikawa
- Department of Physics, University of Tokyo, Hongo, Tokyo, 113-0033, Japan
| | - Gideok Kim
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Daniel Putzky
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Zhi Zhong Li
- Laboratoire de Physique des Solides (CNRS UMR 8502), Bâtiment 510, Université Paris-Saclay, 91405, Orsay, France
| | - Hélène Raffy
- Laboratoire de Physique des Solides (CNRS UMR 8502), Bâtiment 510, Université Paris-Saclay, 91405, Orsay, France
| | - Semyon Germanskiy
- Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany
| | - Jan-Christoph Deinert
- Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany
| | - Nilesh Awari
- Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany.,University of Groningen, 9747 AG, Groningen, Netherlands
| | - Igor Ilyakov
- Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany
| | - Bertram Green
- Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany
| | - Min Chen
- Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany.,Technische Universität Berlin, Institut für Optik und Atomare Physik, Strasse des 17. Juni 135, 10623, Berlin, Germany
| | - Mohammed Bawatna
- Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany
| | - Georg Cristiani
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Gennady Logvenov
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Yann Gallais
- Laboratoire Matériaux et Phénomènes Quantiques (UMR 7162 CNRS), Université de Paris, Bâtiment Condorcet, 75205, Paris Cedex 13, France
| | - Alexander V Boris
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Bernhard Keimer
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Andreas P Schnyder
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Dirk Manske
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Michael Gensch
- Technische Universität Berlin, Institut für Optik und Atomare Physik, Strasse des 17. Juni 135, 10623, Berlin, Germany.,German Aerospace Center (DLR), Institute of Optical Sensor Systems, Rutherfordstrasse 2, 12489, Berlin, Germany
| | - Zhe Wang
- Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328, Dresden, Germany. .,Institute of Physics II, University of Cologne, 50937, Cologne, Germany.
| | - Ryo Shimano
- Department of Physics, University of Tokyo, Hongo, Tokyo, 113-0033, Japan. .,Cryogenic Research Center, University of Tokyo, Hongo, Tokyo, 113-0032, Japan.
| | - Stefan Kaiser
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany. .,4th Physics Institute, University of Stuttgart, 70569, Stuttgart, Germany.
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32
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Cheng B, Kanda N, Ikeda TN, Matsuda T, Xia P, Schumann T, Stemmer S, Itatani J, Armitage NP, Matsunaga R. Efficient Terahertz Harmonic Generation with Coherent Acceleration of Electrons in the Dirac Semimetal Cd_{3}As_{2}. PHYSICAL REVIEW LETTERS 2020; 124:117402. [PMID: 32242712 DOI: 10.1103/physrevlett.124.117402] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/17/2020] [Accepted: 02/21/2020] [Indexed: 05/27/2023]
Abstract
We report strong terahertz (∼10^{12} Hz) high harmonic generation at room temperature in thin films of Cd_{3}As_{2}, a three-dimensional Dirac semimetal. Third harmonics are detectable with a tabletop light source and can be as strong as 100 V/cm by applying a fundamental field of 6.5 kV/cm inside the film, demonstrating an unprecedented efficiency for terahertz frequency conversion. Our time-resolved terahertz spectroscopy and calculations also clarify the microscopic mechanism of the nonlinearity originating in the coherent acceleration of Dirac electrons in momentum space. Our results provide clear insights for nonlinear currents of Dirac electrons driven by the terahertz field under the influence of scattering, paving the way toward novel devices for high-speed electronics and photonics based on topological semimetals.
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Affiliation(s)
- Bing Cheng
- The Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Natsuki Kanda
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Tatsuhiko N Ikeda
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Takuya Matsuda
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Peiyu Xia
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Timo Schumann
- Materials Department, University of California, Santa Barbara, California 93106-5050, USA
| | - Susanne Stemmer
- Materials Department, University of California, Santa Barbara, California 93106-5050, USA
| | - Jiro Itatani
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - N P Armitage
- The Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Ryusuke Matsunaga
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
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33
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Juraschek DM, Meier QN, Narang P. Parametric Excitation of an Optically Silent Goldstone-Like Phonon Mode. PHYSICAL REVIEW LETTERS 2020; 124:117401. [PMID: 32242728 DOI: 10.1103/physrevlett.124.117401] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 01/24/2020] [Accepted: 02/19/2020] [Indexed: 06/11/2023]
Abstract
It has recently been indicated that the hexagonal manganites exhibit Higgs- and Goldstone-like phonon modes that modulate the amplitude and phase of their primary order parameter. Here, we describe a mechanism by which a silent Goldstone-like phonon mode can be coherently excited, which is based on nonlinear coupling to an infrared-active Higgs-like phonon mode. Using a combination of first-principles calculations and phenomenological modeling, we describe the coupled Higgs-Goldstone dynamics in response to the excitation with a terahertz pulse. Besides theoretically demonstrating coherent control of crystallographic Higgs and Goldstone excitations, we show that the previously inaccessible silent phonon modes can be excited coherently with this mechanism.
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Affiliation(s)
- Dominik M Juraschek
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Quintin N Meier
- Department of Materials, ETH Zurich, CH-8093 Zürich, Switzerland
| | - Prineha Narang
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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34
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Novelli F, Tollerud JO, Prabhakaran D, Davis JA. Persistent coherence of quantum superpositions in an optimally doped cuprate revealed by 2D spectroscopy. SCIENCE ADVANCES 2020; 6:eaaw9932. [PMID: 32158934 PMCID: PMC7048423 DOI: 10.1126/sciadv.aaw9932] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 12/05/2019] [Indexed: 05/10/2023]
Abstract
Quantum materials displaying intriguing magnetic and electronic properties could be key to the development of future technologies. However, it is poorly understood how the macroscopic behavior emerges in complex materials with strong electronic correlations. While measurements of the dynamics of excited electronic populations have been able to give some insight, they have largely neglected the intricate dynamics of quantum coherence. Here, we apply multidimensional coherent spectroscopy to a prototypical cuprate and report unprecedented coherent dynamics persisting for ~500 fs, originating directly from the quantum superposition of optically excited states separated by 20 to 60 meV. These results reveal that the states in this energy range are correlated with the optically excited states at ~1.5 eV and point to nontrivial interactions between quantum many-body states on the different energy scales. In revealing these dynamics and correlations, we demonstrate that multidimensional coherent spectroscopy can interrogate complex quantum materials in unprecedented ways.
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Affiliation(s)
- Fabio Novelli
- Centre for Quantum and Optical Science, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
- Department of Physical Chemistry II, Ruhr University Bochum, 44801 Bochum, Germany
| | - Jonathan O. Tollerud
- Centre for Quantum and Optical Science, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
| | | | - Jeffrey A. Davis
- Centre for Quantum and Optical Science, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technologies, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
- Corresponding author.
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35
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Classification and characterization of nonequilibrium Higgs modes in unconventional superconductors. Nat Commun 2020; 11:287. [PMID: 31941881 PMCID: PMC6962398 DOI: 10.1038/s41467-019-13763-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/26/2019] [Indexed: 11/17/2022] Open
Abstract
Recent findings of new Higgs modes in unconventional superconductors require a classification and characterization of the modes allowed by nontrivial gap symmetry. Here we develop a theory for a tailored nonequilibrium quantum quench to excite all possible oscillation symmetries of a superconducting condensate. We show that both a finite momentum transfer and quench symmetry allow for an identification of the resulting Higgs oscillations. These serve as a fingerprint for the ground state gap symmetry. We provide a classification scheme of these oscillations and the quench symmetry based on group theory for the underlying lattice point group. For characterization, analytic calculations as well as full scale numeric simulations of the transient optical response resulting from an excitation by a realistic laser pulse are performed. Our classification of Higgs oscillations allows us to distinguish between different symmetries of the superconducting condensate. The lately reported Higgs modes in unconventional superconductors require a classification and characterization allowed by nontrivial symmetry of the gap and the quench pulses. Here, the authors provide a classification scheme of Higgs oscillations with their excitation processes allowing them to distinguish between different symmetries of the superconducting condensate.
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36
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Theory of Time-Resolved Optical Conductivity of Superconductors: Comparing Two Methods for Its Evaluation. CONDENSED MATTER 2019. [DOI: 10.3390/condmat4030079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Time-resolved optical conductivity is an often used tool to interrogate quantum materials driven out of equilibrium. Theoretically calculating this observable is a complex topic with several approaches discussed in the literature. Using a nonequilibrium Keldysh formalism and a functional derivative approach to the conductivity, we present a comparison of two particular approaches to the calculation of the optical conductivity and their distinguishing features, as applied to a pumped superconductor. The two methods are distinguished by the relative motion of the probe and gate times; either the probe or gate time is kept fixed while the other is swept. We find that both the methods result in same qualitative features of the time-resolved conductivity after pump is over. However, calculating the conductivity by keeping the gate fixed removes artifacts inherent to the other method. We provide software that, based on data for the first method, is able to construct the second approach.
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37
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Tuovinen R, Sentef MA, Gomes da Rocha C, Ferreira MS. Time-resolved impurity-invisibility in graphene nanoribbons. NANOSCALE 2019; 11:12296-12304. [PMID: 31211315 DOI: 10.1039/c9nr02738f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We investigate time-resolved charge transport through graphene nanoribbons supplemented with adsorbed impurity atoms. Depending on the location of the impurities with respect to the hexagonal carbon lattice, the transport properties of the system may become invisible to the impurity due to the symmetry properties of the binding mechanism. This motivates a chemical sensing device since dopants affecting the underlying sublattice symmetry of the pristine graphene nanoribbon introduce scattering. Using the time-dependent Landauer-Büttiker formalism, we extend the stationary current-voltage picture to the transient regime, where we observe how the impurity invisibility takes place at sub-picosecond time scales further motivating ultrafast sensor technology. We further characterize time-dependent local charge and current profiles within the nanoribbons, and we identify rearrangements of the current pathways through the nanoribbons due to the impurities. We finally study the behavior of the transients with ac driving which provides another way of identifying the lattice-symmetry breaking caused by the impurities.
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Affiliation(s)
- Riku Tuovinen
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany.
| | - Michael A Sentef
- Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany.
| | - Claudia Gomes da Rocha
- Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Mauro S Ferreira
- School of Physics, Trinity College Dublin, Dublin 2, Ireland and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
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38
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Nakamura S, Iida Y, Murotani Y, Matsunaga R, Terai H, Shimano R. Infrared Activation of the Higgs Mode by Supercurrent Injection in Superconducting NbN. PHYSICAL REVIEW LETTERS 2019; 122:257001. [PMID: 31347872 DOI: 10.1103/physrevlett.122.257001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 02/07/2019] [Indexed: 06/10/2023]
Abstract
The Higgs mode in superconductors, i.e., the collective amplitude mode of the order parameter, does not associate with charge nor spin fluctuations, therefore it does not couple to the electromagnetic field in the linear response regime. Contrary to this common understanding, here, we demonstrate that if the dc supercurrent is introduced into the superconductor, the Higgs mode becomes infrared active and is directly observed in the linear optical conductivity measurement. We observed a sharp resonant peak at ω=2Δ in the optical conductivity spectrum of a thin-film NbN in the presence of dc supercurrent, showing a reasonable agreement with the recent theoretical prediction. The method as proven by this work opens a new pathway to study the Higgs mode in a wide variety of superconductors.
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Affiliation(s)
- Sachiko Nakamura
- Cryogenic Research Center, the University of Tokyo, Yayoi, Tokyo, 113-0032, Japan
| | - Yudai Iida
- Department of Physics, the University of Tokyo, Hongo, Tokyo, 113-0033, Japan
| | - Yuta Murotani
- Department of Physics, the University of Tokyo, Hongo, Tokyo, 113-0033, Japan
| | - Ryusuke Matsunaga
- The Institute for Solid State Physics, the University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Hirotaka Terai
- National Institute of Information and Communications Technology, 588-2 Iwaoka, Nishi-ku, Kobe 651-2492, Japan
| | - Ryo Shimano
- Cryogenic Research Center, the University of Tokyo, Yayoi, Tokyo, 113-0032, Japan
- Department of Physics, the University of Tokyo, Hongo, Tokyo, 113-0033, Japan
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Hirsbrunner MR, Philip TM, Basa B, Kim Y, Jip Park M, Gilbert MJ. A review of modeling interacting transient phenomena with non-equilibrium Green functions. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:046001. [PMID: 30641508 DOI: 10.1088/1361-6633/aafe5f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
As experimental probes have matured to observe ultrafast transient and high frequency responses of materials and devices, so to have the theoretical methods to numerically and analytically simulate time- and frequency-resolved transport. In this review article, we discuss recent progress in the development of the time-dependent and frequency-dependent non-equilibrium Green function (NEGF) technique. We begin with an overview of the theoretical underpinnings of the underlying Kadanoff-Baym equations and derive the fundamental NEGF equations in the time and frequency domains. We discuss how these methods have been applied to a variety of condensed matter systems such as molecular electronics, nanoscale transistors, and superconductors. In addition, we survey the application of NEGF in fields beyond condensed matter, where it has been used to study thermalization in ultra-cold atoms and to understand leptogenesis in the early universe. Throughout, we pay special attention to the challenges of incorporating contacts and interactions, as the NEGF method is uniquely capable of accounting for such features.
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Affiliation(s)
- Mark R Hirsbrunner
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
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40
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Grasset R, Gallais Y, Sacuto A, Cazayous M, Mañas-Valero S, Coronado E, Méasson MA. Pressure-Induced Collapse of the Charge Density Wave and Higgs Mode Visibility in 2H-TaS_{2}. PHYSICAL REVIEW LETTERS 2019; 122:127001. [PMID: 30978099 DOI: 10.1103/physrevlett.122.127001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Indexed: 06/09/2023]
Abstract
The pressure evolution of the Raman active electronic excitations of the transition metal dichalcogenides 2H-TaS_{2} is followed through the pressure phase diagram embedding incommensurate charge-density-wave and superconducting states. At high pressure, the charge-density wave is found to collapse at 8.5 GPa. In the coexisting charge-density-wave and superconducting orders, we unravel a strong in-gap superconducting mode, attributed to a Higgs mode, coexisting with the expected incoherent Cooper-pair breaking signature. The latter remains in the pure superconducting state reached above 8.5 GPa. Our report constitutes a new observation of such Raman active Higgs mode since the long-standing unique case 2H-NbSe_{2}.
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Affiliation(s)
- Romain Grasset
- Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot, Sorbonne Paris Cité, UMR No. 7162, CNRS, 75013 Paris, France
| | - Yann Gallais
- Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot, Sorbonne Paris Cité, UMR No. 7162, CNRS, 75013 Paris, France
| | - Alain Sacuto
- Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot, Sorbonne Paris Cité, UMR No. 7162, CNRS, 75013 Paris, France
| | - Maximilien Cazayous
- Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot, Sorbonne Paris Cité, UMR No. 7162, CNRS, 75013 Paris, France
| | - Samuel Mañas-Valero
- Universidad de Valencia (ICMol), Catedratico José Beltran Martinez, 46980 Paterna, Spain
| | - Eugenio Coronado
- Universidad de Valencia (ICMol), Catedratico José Beltran Martinez, 46980 Paterna, Spain
| | - Marie-Aude Méasson
- Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot, Sorbonne Paris Cité, UMR No. 7162, CNRS, 75013 Paris, France
- Institut NEEL CNRS/UGA UPR2940, MCBT, 25 rue des Martyrs BP 166, 38042 Grenoble cedex 9, France
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41
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Kurkjian H, Klimin SN, Tempere J, Castin Y. Pair-Breaking Collective Branch in BCS Superconductors and Superfluid Fermi Gases. PHYSICAL REVIEW LETTERS 2019; 122:093403. [PMID: 30932523 DOI: 10.1103/physrevlett.122.093403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Indexed: 06/09/2023]
Abstract
We demonstrate the existence of a collective excitation branch in the pair-breaking continuum of superfluid Fermi gases and BCS superconductors. At zero temperature, we analytically continue the equation on the collective mode energy in Anderson's Random Phase Approximation or Gaussian fluctuations through its branch cut associated with the continuum, and obtain the full complex dispersion relation, including in the strong coupling regime. The branch exists as long as the chemical potential μ is positive and the wave number below sqrt[2mμ]/ℏ (with m the fermion mass). In the long wavelength limit, the branch varies quadratically with the wave number, with a complex effective mass that we compute analytically for an arbitrary interaction strength.
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Affiliation(s)
- H Kurkjian
- Theory of Quantum Complex Systems, Universiteit Antwerpen, Universiteitsplein 1, B-2610 Antwerpen, Belgium
| | - S N Klimin
- Theory of Quantum Complex Systems, Universiteit Antwerpen, Universiteitsplein 1, B-2610 Antwerpen, Belgium
| | - J Tempere
- Theory of Quantum Complex Systems, Universiteit Antwerpen, Universiteitsplein 1, B-2610 Antwerpen, Belgium
| | - Y Castin
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 75231 Paris, France
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42
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Li F, Chernyak VY, Sinitsyn NA. Quantum Annealing and Thermalization: Insights from Integrability. PHYSICAL REVIEW LETTERS 2018; 121:190601. [PMID: 30468584 DOI: 10.1103/physrevlett.121.190601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 06/05/2018] [Indexed: 06/09/2023]
Abstract
We solve a model that has basic features that are desired for quantum annealing computations: entanglement in the ground state, controllable annealing speed, ground state energy separated by a gap during the whole evolution, and a programmable computational problem that is encoded by parameters of the Ising part of the spin Hamiltonian. Our solution enables exact nonperturbative characterization of final nonadiabatic excitations, including a scaling of their number with the annealing rate and the system size. We prove that quantum correlations can accelerate computations and, at the end of the annealing protocol, lead to the perfect Gibbs distribution of all microstates.
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Affiliation(s)
- Fuxiang Li
- School of Physics and Electronics, Hunan University, Changsha 410082, China, Theoretical Division, Los Alamos National Laboratory, B213, Los Alamos, New Mexico 87545, USA and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Vladimir Y Chernyak
- Department of Chemistry and Department of Mathematics, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Nikolai A Sinitsyn
- Theoretical Division, Los Alamos National Laboratory, B213, Los Alamos, New Mexico 87545, USA
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43
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Yang X, Vaswani C, Sundahl C, Mootz M, Gagel P, Luo L, Kang JH, Orth PP, Perakis IE, Eom CB, Wang J. Terahertz-light quantum tuning of a metastable emergent phase hidden by superconductivity. NATURE MATERIALS 2018; 17:586-591. [PMID: 29867167 DOI: 10.1038/s41563-018-0096-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 04/30/2018] [Indexed: 06/08/2023]
Abstract
'Sudden' quantum quench and prethermalization have become a cross-cutting theme for discovering emergent states of matter1-4. Yet this remains challenging in electron matter5-9, especially superconductors10-14. The grand question of what is hidden underneath superconductivity (SC) 15 appears universal, but poorly understood. Here we reveal a long-lived gapless quantum phase of prethermalized quasiparticles (QPs) after a single-cycle terahertz (THz) quench of a Nb3Sn SC gap. Its conductivity spectra is characterized by a sharp coherent peak and a vanishing scattering rate that decreases almost linearly towards zero frequency, which is most pronounced around the full depletion of the condensate and absent for a high-frequency pump. Above a critical pump threshold, such a QP phase with coherent transport and memory persists as an unusual prethermalization plateau, without relaxation to normal and SC thermal states for an order of magnitude longer than the QP recombination and thermalization times. Switching to this metastable 'quantum QP fluid' signals non-thermal quench of coupled SC and charge-density-wave (CDW)-like orders and hints quantum control beneath the SC.
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Affiliation(s)
- X Yang
- Department of Physics and Astronomy, Ames Laboratory, Iowa State University, Ames, IA, USA
| | - C Vaswani
- Department of Physics and Astronomy, Ames Laboratory, Iowa State University, Ames, IA, USA
| | - C Sundahl
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - M Mootz
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - P Gagel
- Institute for Solid State Physics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - L Luo
- Department of Physics and Astronomy, Ames Laboratory, Iowa State University, Ames, IA, USA
| | - J H Kang
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - P P Orth
- Department of Physics and Astronomy, Ames Laboratory, Iowa State University, Ames, IA, USA
| | - I E Perakis
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - C B Eom
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - J Wang
- Department of Physics and Astronomy, Ames Laboratory, Iowa State University, Ames, IA, USA.
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44
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Sinitsyn NA, Yuzbashyan EA, Chernyak VY, Patra A, Sun C. Integrable Time-Dependent Quantum Hamiltonians. PHYSICAL REVIEW LETTERS 2018; 120:190402. [PMID: 29799228 DOI: 10.1103/physrevlett.120.190402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 03/22/2018] [Indexed: 06/08/2023]
Abstract
We formulate a set of conditions under which the nonstationary Schrödinger equation with a time-dependent Hamiltonian is exactly solvable analytically. The main requirement is the existence of a non-Abelian gauge field with zero curvature in the space of system parameters. Known solvable multistate Landau-Zener models satisfy these conditions. Our method provides a strategy to incorporate time dependence into various quantum integrable models while maintaining their integrability. We also validate some prior conjectures, including the solution of the driven generalized Tavis-Cummings model.
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Affiliation(s)
- Nikolai A Sinitsyn
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Emil A Yuzbashyan
- Center for Materials Theory, Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Vladimir Y Chernyak
- Department of Chemistry and Department of Mathematics, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Aniket Patra
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- Center for Materials Theory, Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Chen Sun
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- Department of Physics, Texas A&M University, Texas 77840, USA
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45
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Katsumi K, Tsuji N, Hamada YI, Matsunaga R, Schneeloch J, Zhong RD, Gu GD, Aoki H, Gallais Y, Shimano R. Higgs Mode in the d-Wave Superconductor Bi_{2}Sr_{2}CaCu_{2}O_{8+x} Driven by an Intense Terahertz Pulse. PHYSICAL REVIEW LETTERS 2018; 120:117001. [PMID: 29601772 DOI: 10.1103/physrevlett.120.117001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 02/05/2018] [Indexed: 06/08/2023]
Abstract
We investigate the terahertz (THz)-pulse-driven nonlinear response in the d-wave cuprate superconductor Bi_{2}Sr_{2}CaCu_{2}O_{8+x} (Bi2212) using a THz pump near-infrared probe scheme in the time domain. We observe an oscillatory behavior of the optical reflectivity that follows the THz electric field squared and is markedly enhanced below T_{c}. The corresponding third-order nonlinear effect exhibits both A_{1g} and B_{1g} symmetry components, which are decomposed from polarization-resolved measurements. A comparison with a BCS calculation of the nonlinear susceptibility indicates that the A_{1g} component is associated with the Higgs mode of the d-wave order parameter.
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Affiliation(s)
- Kota Katsumi
- Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan
| | - Naoto Tsuji
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - Yuki I Hamada
- Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan
| | - Ryusuke Matsunaga
- Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan
- JST, PRESTO, Kawaguchi 332-0012, Japan
| | | | | | - Genda D Gu
- Brookhaven National Lab, Upton, New York 11973, USA
| | - Hideo Aoki
- Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan
- Department of Physics, ETH Zürich, 8093 Zürich, Switzerland
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568, Japan
| | - Yann Gallais
- Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan
- MPQ CNRS, Université Paris Diderot, Bâtiment Condorcet, 75205 Paris Cedex 13, France
- Cryogenic Research Center, The University of Tokyo, Tokyo 113-0032, Japan
| | - Ryo Shimano
- Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan
- Cryogenic Research Center, The University of Tokyo, Tokyo 113-0032, Japan
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46
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Werdehausen D, Takayama T, Höppner M, Albrecht G, Rost AW, Lu Y, Manske D, Takagi H, Kaiser S. Coherent order parameter oscillations in the ground state of the excitonic insulator Ta 2NiSe 5. SCIENCE ADVANCES 2018; 4:eaap8652. [PMID: 29740599 PMCID: PMC5938280 DOI: 10.1126/sciadv.aap8652] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 02/12/2018] [Indexed: 05/29/2023]
Abstract
The excitonic insulator is an intriguing electronic phase of condensed excitons. A prominent candidate is the small bandgap semiconductor Ta2NiSe5, in which excitons are believed to undergo a Bose-Einstein condensation-like transition. However, direct experimental evidence for the existence of a coherent condensate in this material is still missing. A direct fingerprint of such a state would be the observation of its collective modes, which are equivalent to the Higgs and Goldstone modes in superconductors. We report evidence for the existence of a coherent amplitude response in the excitonic insulator phase of Ta2NiSe5. Using nonlinear excitations with short laser pulses, we identify a phonon-coupled state of the condensate that can be understood as a novel amplitude mode. The condensate density contribution substantiates the picture of an electronically driven phase transition and characterizes the transient order parameter of the excitonic insulator as a function of temperature and excitation density.
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Affiliation(s)
- Daniel Werdehausen
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- 4th Physics Institute, University of Stuttgart, 70569 Stuttgart, Germany
| | - Tomohiro Takayama
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, 70569 Stuttgart, Germany
| | - Marc Höppner
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Gelon Albrecht
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- 4th Physics Institute, University of Stuttgart, 70569 Stuttgart, Germany
| | - Andreas W. Rost
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, 70569 Stuttgart, Germany
| | - Yangfan Lu
- Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Dirk Manske
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Hidenori Takagi
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, 70569 Stuttgart, Germany
- Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Stefan Kaiser
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- 4th Physics Institute, University of Stuttgart, 70569 Stuttgart, Germany
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47
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Murakami Y, Golež D, Eckstein M, Werner P. Photoinduced Enhancement of Excitonic Order. PHYSICAL REVIEW LETTERS 2017; 119:247601. [PMID: 29286755 DOI: 10.1103/physrevlett.119.247601] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Indexed: 06/07/2023]
Abstract
We study the dynamics of excitonic insulators coupled to phonons using the time-dependent mean-field theory. Without phonon couplings, the linear response is given by the damped amplitude oscillations of the order parameter with a frequency equal to the minimum band gap. A phonon coupling to the interband transfer integral induces two types of long-lived collective oscillations of the amplitude, one originating from the phonon dynamics and the other from the phase mode, which becomes massive. We show that, even for small phonon coupling, a photoinduced enhancement of the exciton condensation and the gap can be realized. Using the Anderson pseudospin picture, we argue that the origin of the enhancement is a cooperative effect of the massive phase mode and the Hartree shift induced by the photoexcitation. We also discuss how the enhancement of the order and the collective modes can be observed with time-resolved photoemission spectroscopy.
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Affiliation(s)
- Yuta Murakami
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Denis Golež
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Martin Eckstein
- Department of Physics, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Philipp Werner
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
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48
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Léonard J, Morales A, Zupancic P, Donner T, Esslinger T. Monitoring and manipulating Higgs and Goldstone modes in a supersolid quantum gas. Science 2017; 358:1415-1418. [DOI: 10.1126/science.aan2608] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 11/03/2017] [Indexed: 11/02/2022]
Abstract
Higgs and Goldstone modes are collective excitations of the amplitude and phase of an order parameter that is related to the breaking of a continuous symmetry. We directly studied these modes in a supersolid quantum gas created by coupling a Bose-Einstein condensate to two optical cavities, whose field amplitudes form the real and imaginary parts of a U(1)-symmetric order parameter. Monitoring the cavity fields in real time allowed us to observe the dynamics of the associated Higgs and Goldstone modes and revealed their amplitude and phase nature. We used a spectroscopic method to measure their frequencies, and we gave a tunable mass to the Goldstone mode by exploring the crossover between continuous and discrete symmetry. Our experiments link spectroscopic measurements to the theoretical concept of Higgs and Goldstone modes.
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49
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Ido K, Ohgoe T, Imada M. Correlation-induced superconductivity dynamically stabilized and enhanced by laser irradiation. SCIENCE ADVANCES 2017; 3:e1700718. [PMID: 28835923 PMCID: PMC5562419 DOI: 10.1126/sciadv.1700718] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 07/18/2017] [Indexed: 06/07/2023]
Abstract
Studies on out-of-equilibrium dynamics have paved a way to realize a new state of matter. Superconductor-like properties above room temperatures recently suggested to be in copper oxides achieved by selectively exciting vibrational phonon modes by laser have inspired studies on an alternative and general strategy to be pursued for high-temperature superconductivity. We show that the superconductivity can be enhanced by irradiating laser to correlated electron systems owing to two mechanisms: First, the effective attractive interaction of carriers is enhanced by the dynamical localization mechanism, which drives the system into strong coupling regions. Second, the irradiation allows reaching uniform and enhanced superconductivity dynamically stabilized without deteriorating into equilibrium inhomogeneities that suppress superconductivity. The dynamical superconductivity is subject to the Higgs oscillations during and after the irradiation. Our finding sheds light on a way to enhance superconductivity that is inaccessible in equilibrium in strongly correlated electron systems.
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50
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Dutta S, Mueller EJ. Collective Modes of a Soliton Train in a Fermi Superfluid. PHYSICAL REVIEW LETTERS 2017; 118:260402. [PMID: 28707921 DOI: 10.1103/physrevlett.118.260402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Indexed: 06/07/2023]
Abstract
We characterize the collective modes of a soliton train in a quasi-one-dimensional Fermi superfluid, using a mean-field formalism. In addition to the expected Goldstone and Higgs modes, we find novel long-lived gapped modes associated with oscillations of the soliton cores. The soliton train has an instability that depends strongly on the interaction strength and the spacing of solitons. It can be stabilized by filling each soliton with an unpaired fermion, thus forming a commensurate Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase. We find that such a state is always dynamically stable, which paves the way for realizing long-lived FFLO states in experiments via phase imprinting.
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Affiliation(s)
- Shovan Dutta
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
| | - Erich J Mueller
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
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