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Chen XY, Biswas S, Eppelt S, Schindewolf A, Deng F, Shi T, Yi S, Hilker TA, Bloch I, Luo XY. Ultracold field-linked tetratomic molecules. Nature 2024; 626:283-287. [PMID: 38297128 PMCID: PMC10849947 DOI: 10.1038/s41586-023-06986-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 12/15/2023] [Indexed: 02/02/2024]
Abstract
Ultracold polyatomic molecules offer opportunities1 in cold chemistry2,3, precision measurements4 and quantum information processing5,6, because of their rich internal structure. However, their increased complexity compared with diatomic molecules presents a challenge in using conventional cooling techniques. Here we demonstrate an approach to create weakly bound ultracold polyatomic molecules by electroassociation7 (F.D. et al., manuscript in preparation) in a degenerate Fermi gas of microwave-dressed polar molecules through a field-linked resonance8-11. Starting from ground-state NaK molecules, we create around 1.1 × 103 weakly bound tetratomic (NaK)2 molecules, with a phase space density of 0.040(3) at a temperature of 134(3) nK, more than 3,000 times colder than previously realized tetratomic molecules12. We observe a maximum tetramer lifetime of 8(2) ms in free space without a notable change in the presence of an optical dipole trap, indicating that these tetramers are collisionally stable. Moreover, we directly image the dissociated tetramers through microwave-field modulation to probe the anisotropy of their wavefunction in momentum space. Our result demonstrates a universal tool for assembling weakly bound ultracold polyatomic molecules from smaller polar molecules, which is a crucial step towards Bose-Einstein condensation of polyatomic molecules and towards a new crossover from a dipolar Bardeen-Cooper-Schrieffer superfluid13-15 to a Bose-Einstein condensation of tetramers. Moreover, the long-lived field-linked state provides an ideal starting point for deterministic optical transfer to deeply bound tetramer states16-18.
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Affiliation(s)
- Xing-Yan Chen
- Max-Planck-Institut für Quantenoptik, Garching, Germany
- Munich Center for Quantum Science and Technology, Munich, Germany
| | - Shrestha Biswas
- Max-Planck-Institut für Quantenoptik, Garching, Germany
- Munich Center for Quantum Science and Technology, Munich, Germany
| | - Sebastian Eppelt
- Max-Planck-Institut für Quantenoptik, Garching, Germany
- Munich Center for Quantum Science and Technology, Munich, Germany
| | - Andreas Schindewolf
- Max-Planck-Institut für Quantenoptik, Garching, Germany
- Munich Center for Quantum Science and Technology, Munich, Germany
| | - Fulin Deng
- School of Physics and Technology, Wuhan University, Wuhan, China
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China
| | - Tao Shi
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China.
- AS Center for Excellence in Topological Quantum Computation & School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
| | - Su Yi
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China
- AS Center for Excellence in Topological Quantum Computation & School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
- Peng Huanwu Collaborative Center for Research and Education, Beihang University, Beijing, China
| | - Timon A Hilker
- Max-Planck-Institut für Quantenoptik, Garching, Germany
- Munich Center for Quantum Science and Technology, Munich, Germany
| | - Immanuel Bloch
- Max-Planck-Institut für Quantenoptik, Garching, Germany
- Munich Center for Quantum Science and Technology, Munich, Germany
- Fakultät für Physik, Ludwig-Maximilians-Universität, Munich, Germany
| | - Xin-Yu Luo
- Max-Planck-Institut für Quantenoptik, Garching, Germany.
- Munich Center for Quantum Science and Technology, Munich, Germany.
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2
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Yang ZH, Ye YL, Zhou B, Baba H, Chen RJ, Ge YC, Hu BS, Hua H, Jiang DX, Kimura M, Li C, Li KA, Li JG, Li QT, Li XQ, Li ZH, Lou JL, Nishimura M, Otsu H, Pang DY, Pu WL, Qiao R, Sakaguchi S, Sakurai H, Satou Y, Togano Y, Tshoo K, Wang H, Wang S, Wei K, Xiao J, Xu FR, Yang XF, Yoneda K, You HB, Zheng T. Observation of the Exotic 0_{2}^{+} Cluster State in ^{8}He. PHYSICAL REVIEW LETTERS 2023; 131:242501. [PMID: 38181133 DOI: 10.1103/physrevlett.131.242501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 09/05/2023] [Accepted: 11/01/2023] [Indexed: 01/07/2024]
Abstract
We report here the first observation of the 0_{2}^{+} state of ^{8}He, which has been predicted to feature the condensatelike α+^{2}n+^{2}n cluster structure. We show that this state is characterized by a spin parity of 0^{+}, a large isoscalar monopole transition strength, and the emission of a strongly correlated neutron pair, in line with theoretical predictions. Our finding is further supported by the state-of-the-art microscopic α+4n model calculations. The present results may lead to new insights into clustering in neutron-rich nuclear systems and the pair correlation and condensation in quantum many-body systems under strong interactions.
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Affiliation(s)
- Z H Yang
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y L Ye
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - B Zhou
- Key Laboratory of Nuclear Physics and Ion-beam Application (MOE), Institute of Modern Physics, Fudan University, Shanghai 200433, China
- Shanghai Research Center for Theoretical Nuclear Physics, NSFC and Fudan University, Shanghai 200438, China
- Department of Physics, Hokkaido University, 060-0810 Sapporo, Japan
| | - H Baba
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - R J Chen
- Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000, China
| | - Y C Ge
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - B S Hu
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - H Hua
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - D X Jiang
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - M Kimura
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Physics, Hokkaido University, 060-0810 Sapporo, Japan
- Nuclear Reaction Data Centre, Hokkaido University, 060-0810 Sapporo, Japan
| | - C Li
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K A Li
- Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000, China
| | - J G Li
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - Q T Li
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - X Q Li
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - Z H Li
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - J L Lou
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - M Nishimura
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H Otsu
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - D Y Pang
- School of Physics and Beijing Key Laboratory of Advanced Nuclear Materials and Physics, Beihang University, Beijing 100191, China
| | - W L Pu
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - R Qiao
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - S Sakaguchi
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Physics, Kyushu University, 819-0395 Fukuoka, Japan
| | - H Sakurai
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Y Satou
- Rare Isotope Science Project, Institute for Basic Science, Daejeon 34000, Republic of Korea
| | - Y Togano
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Tshoo
- Rare Isotope Science Project, Institute for Basic Science, Daejeon 34000, Republic of Korea
| | - H Wang
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Oh-Okayama, Meguro, Tokyo 152-8551, Japan
| | - S Wang
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Wei
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - J Xiao
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - F R Xu
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - X F Yang
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - K Yoneda
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - H B You
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - T Zheng
- School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
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Majtey AP, Valdés-Hernández A, Cuestas E. Indistinguishable entangled fermions: basics and future challenges. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20220108. [PMID: 37517438 DOI: 10.1098/rsta.2022.0108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 03/26/2023] [Indexed: 08/01/2023]
Abstract
The study of entanglement in systems composed of identical particles raises interesting challenges with far-reaching implications in both, our fundamental understanding of the physics of composite quantum systems, and our capability of exploiting quantum indistinguishability as a resource in quantum information theory. Impressive theoretical and experimental advances have been made in the last decades that bring us closer to a deeper comprehension and to a better control of entanglement. Yet, when it involves composites of indistinguishable quantum systems, the very meaning of entanglement, and hence its characterization, still finds controversy and lacks a widely accepted definition. The aim of the present paper is to introduce, within an accessible and self-contained exposition, the basic ideas behind one of the approaches advanced towards the construction of a coherent definition of entanglement in systems of indistinguishable particles, with focus on fermionic systems. We also inquire whether the corresponding tools developed for studying entanglement in identical-fermion systems can be exploited when analysing correlations in distinguishable-party systems, in which the complete information of the individual parts is not available. Further, we open the discussion on the broader problem of constructing a suitable framework that accommodates entanglement in the presence of generalized statistics. This article is part of the theme issue 'Identity, individuality and indistinguishability in physics and mathematics'.
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Affiliation(s)
- Ana P Majtey
- Instituto de Física Enrique Gaviola, CONICET and Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba X5016LAE, Argentina
| | - Andrea Valdés-Hernández
- Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, Ciudad de México, Mexico
| | - Eloisa Cuestas
- Instituto de Física Enrique Gaviola, CONICET and Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba X5016LAE, Argentina
- Quantum Systems Unit, OIST Graduate University, Onna,Okinawa 904-0495, Japan
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4
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Koch J, Menon K, Cuestas E, Barbosa S, Lutz E, Fogarty T, Busch T, Widera A. A quantum engine in the BEC-BCS crossover. Nature 2023; 621:723-727. [PMID: 37758889 PMCID: PMC10533395 DOI: 10.1038/s41586-023-06469-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 07/21/2023] [Indexed: 09/29/2023]
Abstract
Heat engines convert thermal energy into mechanical work both in the classical and quantum regimes1. However, quantum theory offers genuine non-classical forms of energy, different from heat, which so far have not been exploited in cyclic engines. Here we experimentally realize a quantum many-body engine fuelled by the energy difference between fermionic and bosonic ensembles of ultracold particles that follows from the Pauli exclusion principle2. We employ a harmonically trapped superfluid gas of 6Li atoms close to a magnetic Feshbach resonance3 that allows us to effectively change the quantum statistics from Bose-Einstein to Fermi-Dirac, by tuning the gas between a Bose-Einstein condensate of bosonic molecules and a unitary Fermi gas (and back) through a magnetic field4-10. The quantum nature of such a Pauli engine is revealed by contrasting it with an engine in the classical thermal regime and with a purely interaction-driven device. We obtain a work output of several 106 vibrational quanta per cycle with an efficiency of up to 25%. Our findings establish quantum statistics as a useful thermodynamic resource for work production.
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Affiliation(s)
- Jennifer Koch
- Department of Physics and Research Center OPTIMAS, RPTU Kaiserslautern-Landau, Kaiserslautern, Germany
| | | | - Eloisa Cuestas
- OIST Graduate University, Onna, Japan
- Enrique Gaviola Institute of Physics, National Scientific and Technical Research Council of Argentina and National University of Córdoba, Córdoba, Argentina
| | - Sian Barbosa
- Department of Physics and Research Center OPTIMAS, RPTU Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Eric Lutz
- Institute for Theoretical Physics I, University of Stuttgart, Stuttgart, Germany
| | | | | | - Artur Widera
- Department of Physics and Research Center OPTIMAS, RPTU Kaiserslautern-Landau, Kaiserslautern, Germany.
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5
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Lou X, Yao L, Zhang J, Sui N, Wu M, Zhang W, Kang Z, Chi X, Zhou Q, Zhang H, Wang Y. Competition of Carrier Kinetics Contributes to Amplified Spontaneous Emission in Quasi-2D/3D (PBA) 2MA n-1Pb nBr 3n+1 Thin Films under Strip Light Mode. J Phys Chem Lett 2023; 14:4050-4057. [PMID: 37093818 DOI: 10.1021/acs.jpclett.3c00490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Quasi-2D halide perovskites have potential in lasing due to their amplified spontaneous emission (ASE) properties. The ASE of (PBA)2MAn-1PbnBr3n+1 thin films has been confirmed by photoluminescence (PL) testing using stripe light excitation (SLE). The ASE threshold decreases with decreasing environmental temperature (TE) or increasing number of inorganic layers (n). Using the transient absorption technique, the Auger recombination and the cooling process of the high-activity carrier are accelerated with the decrease of n or TE. A new ASE mechanism is proposed where high-activity carriers directly emit photons under photon perturbation from adjacent sites, leading to the accumulation and amplification of emitted photons only in the SLE region for ASE to occur. In addition, the reduction of n promotes light scattering between nano-thin layers, which supports a rapid increase in the ASE signal after the ASE threshold is crossed.
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Affiliation(s)
- Xue Lou
- Femtosecond Laser Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries, College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Lianfei Yao
- Femtosecond Laser Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries, College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Jiaqi Zhang
- Key Laboratory of Automobile Materials, Ministry of Education, College of Materials Science and Engineering, Jilin University, Changchun 130012, China
| | - Ning Sui
- Femtosecond Laser Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries, College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Min Wu
- Shandong Key Laboratory of Optical Communication Science and Technology, School of Physics Science and Information Technology, Liaocheng University, Liaocheng 252000, China
| | - Wei Zhang
- School of Physics and Materials Science, Guangzhou University, Guangzhou, 510006, China
- Research Center for Advanced Information Materials (CAIM), Huangpu Research and Graduate School of Guangzhou University, Guangzhou 510006, China
| | - Zhihui Kang
- Femtosecond Laser Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries, College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Xiaochun Chi
- Femtosecond Laser Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries, College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Qiang Zhou
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China
| | - Hanzhuang Zhang
- Femtosecond Laser Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries, College of Physics, Jilin University, Changchun 130012, P. R. China
| | - Yinghui Wang
- Femtosecond Laser Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries, College of Physics, Jilin University, Changchun 130012, P. R. China
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6
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Abstract
Scattering resonances are an essential tool for controlling the interactions of ultracold atoms and molecules. However, conventional Feshbach scattering resonances1, which have been extensively studied in various platforms1-7, are not expected to exist in most ultracold polar molecules because of the fast loss that occurs when two molecules approach at a close distance8-10. Here we demonstrate a new type of scattering resonance that is universal for a wide range of polar molecules. The so-called field-linked resonances11-14 occur in the scattering of microwave-dressed molecules because of stable macroscopic tetramer states in the intermolecular potential. We identify two resonances between ultracold ground-state sodium-potassium molecules and use the microwave frequencies and polarizations to tune the inelastic collision rate by three orders of magnitude, from the unitary limit to well below the universal regime. The field-linked resonance provides a tuning knob to independently control the elastic contact interaction and the dipole-dipole interaction, which we observe as a modification in the thermalization rate. Our result provides a general strategy for resonant scattering between ultracold polar molecules, which paves the way for realizing dipolar superfluids15 and molecular supersolids16, as well as assembling ultracold polyatomic molecules.
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7
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Morita Y, Yoshioka K, Kuwata-Gonokami M. Observation of Bose-Einstein condensates of excitons in a bulk semiconductor. Nat Commun 2022; 13:5388. [PMID: 36104375 PMCID: PMC9474864 DOI: 10.1038/s41467-022-33103-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 08/31/2022] [Indexed: 11/25/2022] Open
Abstract
An unambiguous observation of the Bose-Einstein condensation (BEC) of excitons in a photoexcited bulk semiconductor and elucidation of its inherent nature have been longstanding problems in condensed matter physics. Here, we observe the quantum phase transition and a Bose-Einstein condensate appearing in a trapped gas of 1s paraexcitons in bulk Cu2O below 400 mK, by directly visualizing the exciton cloud in real space using mid-infrared induced absorption imaging that we realized in a dilution refrigerator. Our study shows that the paraexciton condensate is undetectable by conventional luminescence spectroscopy. We find an unconventionally small condensate fraction of 0.016 with the spatial profile of the condensate well described by mean-field theory. Our discovery of this new type of BEC in the purely matter-like exciton system interacting with a cold phonon bath could pave the way for the classification of its long-range order, and for essential understanding of quantum statistical mechanics of non-equilibrium open systems. Bose-Einstein condensate of excitons is expected in photo-excited bulk semiconductors, but a direct experimental evidence has been lacking. Here the authors report the observation of a condensate of 1s paraexcitons in Cu2O using real-space mid-infrared absorption imaging realized in a dilution refrigerator.
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8
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Li B, Qin W, Jiao YF, Zhai CL, Xu XW, Kuang LM, Jing H. Optomechanical Schrödinger cat states in a cavity Bose-Einstein condensate. FUNDAMENTAL RESEARCH 2022. [DOI: 10.1016/j.fmre.2022.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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9
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Adhikari SK. Spatial order in a two-dimensional spin-orbit-coupled spin-1/2 condensate: superlattice, multi-ring and stripe formation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:425402. [PMID: 34289454 DOI: 10.1088/1361-648x/ac16ab] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate the formation of stable spatially-ordered states in auniformand alsotrappedquasi-two-dimensional (quasi-2D) Rashba or Dresselhaus spin-orbit (SO) coupled pseudo spin-1/2 Bose-Einstein condensate using the mean-field Gross-Pitaevskii equation. For weak SO coupling, one can have a circularly-symmetric (0, +1)- or (0, -1)-type multi-ring state with intrinsic vorticity, for Rashba or Dresselhaus SO coupling, respectively, where the numbers in the parentheses denote the net angular momentum projection in the two components, in addition to a circularly-asymmetric degenerate state with zero net angular momentum projection. For intermediate SO couplings, in addition to the above two types, one can also have states with stripe pattern in component densities with no periodic modulation in total density. The stripe state continues to exist for large SO coupling. In addition, a new spatially-periodic state appears in the uniform system: asuperlatticestate, possessing some properties of asupersolid, with a square-lattice pattern in component densities and also in total density. In a trapped system the superlattice state is slightly different with multi-ring pattern in component density and a square-lattice pattern in total density. For an equal mixture of Rashba and Dresselhaus SO couplings, in both uniform and trapped systems, only stripe states are found for all strengths of SO couplings. In a uniform system all these states are quasi-2D solitonic states.
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Affiliation(s)
- S K Adhikari
- Instituto de Física Teórica, Universidade Estadual Paulista-UNESP, 01.140-070 São Paulo, São Paulo, Brazil
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10
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Hachmann M, Kiefer Y, Riebesehl J, Eichberger R, Hemmerich A. Quantum Degenerate Fermi Gas in an Orbital Optical Lattice. PHYSICAL REVIEW LETTERS 2021; 127:033201. [PMID: 34328765 DOI: 10.1103/physrevlett.127.033201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
Spin-polarized samples and spin mixtures of quantum degenerate fermionic atoms are prepared in selected excited Bloch bands of an optical checkerboard square lattice. For the spin-polarized case, extreme band lifetimes above 10 s are observed, reflecting the suppression of collisions by Pauli's exclusion principle. For spin mixtures, lifetimes are reduced by an order of magnitude by two-body collisions between different spin components, but still remarkably large values of about 1 s are found. By analyzing momentum spectra, we can directly observe the orbital character of the optical lattice. The observations demonstrated here form the basis for exploring the physics of Fermi gases with two paired spin components in orbital optical lattices, including the regime of unitarity.
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Affiliation(s)
- M Hachmann
- Institut für Laserphysik, Universität Hamburg, 22761 Hamburg, Germany
- Zentrum für Optische Quantentechnologien, Universität Hamburg, 22761 Hamburg, Germany
| | - Y Kiefer
- Institut für Laserphysik, Universität Hamburg, 22761 Hamburg, Germany
- Zentrum für Optische Quantentechnologien, Universität Hamburg, 22761 Hamburg, Germany
| | - J Riebesehl
- Institut für Laserphysik, Universität Hamburg, 22761 Hamburg, Germany
| | - R Eichberger
- Institut für Laserphysik, Universität Hamburg, 22761 Hamburg, Germany
- Zentrum für Optische Quantentechnologien, Universität Hamburg, 22761 Hamburg, Germany
| | - A Hemmerich
- Institut für Laserphysik, Universität Hamburg, 22761 Hamburg, Germany
- Zentrum für Optische Quantentechnologien, Universität Hamburg, 22761 Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Universität Hamburg, 22761 Hamburg, Germany
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11
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Adhikari SK. Supersolid-like states in a two-dimensional trapped spin-orbit-coupled spin-1 condensate. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:265402. [PMID: 33882472 DOI: 10.1088/1361-648x/abfa5f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/21/2021] [Indexed: 06/12/2023]
Abstract
We study supersolid-like states in a quasi-two-dimensional trapped Rashba and Dresselhaus spin-orbit (SO) coupled spin-1 condensate. For small strengths of SO couplingγ(γ⪅ 0.75), in the ferromagnetic phase, circularly-symmetric (0, ±1, ±2)- and (∓1, 0, ±1)-type states are formed where the numbers in the parentheses denote the angular momentum of the vortex at the center of the components and where the upper (lower) sign correspond to Rashba (Dresselhaus) coupling; in the antiferromagnetic phase, only (∓1, 0, ±1)-type states are formed. For large strengths of SO coupling, supersolid-like superlattice and superstripe states are formed in the ferromagnetic phase. In the antiferromagnetic phase, for large strengths of SO coupling, supersolid-like superstripe and multi-ring states are formed. For an equal mixture of Rashba and Dresselhaus SO couplings, only a superstripe state is found. All these states are found to be dynamically stable and hence accessible in an experiment and will enhance the fundamental understanding of crystallization onto radially periodic states in solids.
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Affiliation(s)
- S K Adhikari
- Instituto de Física Teórica, Universidade Estadual Paulista-UNESP, 01.140-070 São Paulo, São Paulo, Brazil
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12
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Cuestas E, Majtey AP. A generalized molecule approach capturing the Feshbach-induced pairing physics in the BEC-BCS crossover. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:255601. [PMID: 33848988 DOI: 10.1088/1361-648x/abf7a2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 04/13/2021] [Indexed: 06/12/2023]
Abstract
By including the effect of a trap with characteristic energy given by the Fermi temperatureTFin a two-body two-channel model for Feshbach resonances, we reproduce the measured binding energy of ultracold molecules in a40K atomic Fermi gas. We also reproduce the experimental closed-channel fractionZacross the BEC-BCS crossover and into the BCS regime of a6Li atomic Fermi gas. We obtain the expected behaviorZ∝TFat unitarity, together with the recently measured proportionality constant. Our results are also in agreement with recent measurements of theZdependency onTFon the BCS side, where a significant quantitative discrepancy between experimental data and theory's predictions has been repeatedly reported. In order to contrast with future experiments we report the proportionality constant at unitarity betweenZandTFpredicted by our model for a40K atomic Fermi gas.
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Affiliation(s)
- Eloisa Cuestas
- Facultad de Matemática, Astronomía, Física y Computación (FaMAF), Universidad Nacional de Córdoba (UNC), Av. Medina Allende s/n, Ciudad Universitaria, X5000HUA, Córdoba, Argentina
- Instituto de Física Enrique Gaviola (IFEG), Consejo de Investigaciones Científicas y Técnicas de la República Argentina (CONICET), Córdoba, Argentina
| | - Ana P Majtey
- Facultad de Matemática, Astronomía, Física y Computación (FaMAF), Universidad Nacional de Córdoba (UNC), Av. Medina Allende s/n, Ciudad Universitaria, X5000HUA, Córdoba, Argentina
- Instituto de Física Enrique Gaviola (IFEG), Consejo de Investigaciones Científicas y Técnicas de la República Argentina (CONICET), Córdoba, Argentina
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13
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Nakagawa Y, Kasahara Y, Nomoto T, Arita R, Nojima T, Iwasa Y. Gate-controlled BCS-BEC crossover in a two-dimensional superconductor. Science 2021; 372:190-195. [PMID: 33737401 DOI: 10.1126/science.abb9860] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 03/05/2021] [Indexed: 11/02/2022]
Abstract
Bardeen-Cooper-Schrieffer (BCS) superfluidity and Bose-Einstein condensation (BEC) are the two extreme limits of the ground state of the paired fermion systems. We report crossover behavior from the BCS limit to the BEC limit realized by varying carrier density in a two-dimensional superconductor, electron-doped zirconium nitride chloride. The phase diagram, established by simultaneous measurements of resistivity and tunneling spectra under ionic gating, demonstrates a pseudogap phase in the low-doping regime. The ratio of the superconducting transition temperature and Fermi temperature in the low-carrier density limit is consistent with the theoretical upper bound expected in the BCS-BEC crossover regime. These results indicate that the gate-doped semiconductor provides an ideal platform for the two-dimensional BCS-BEC crossover without added complexities present in other solid-state systems.
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Affiliation(s)
- Yuji Nakagawa
- Department of Applied Physics, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan.,Quantum-Phase Electronics Center, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Yuichi Kasahara
- Department of Physics, Kyoto University, Kitashirakawa Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Takuya Nomoto
- Department of Applied Physics, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Ryotaro Arita
- Department of Applied Physics, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan.,RIKEN Center for Emergent Matter Science, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
| | - Tsutomu Nojima
- Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-0812, Japan
| | - Yoshihiro Iwasa
- Department of Applied Physics, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan. .,Quantum-Phase Electronics Center, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan.,RIKEN Center for Emergent Matter Science, Hirosawa 2-1, Wako, Saitama 351-0198, Japan
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14
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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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15
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Diniz PC, Oliveira EAB, Lima ARP, Henn EAL. Ground state and collective excitations of a dipolar Bose-Einstein condensate in a bubble trap. Sci Rep 2020; 10:4831. [PMID: 32179828 PMCID: PMC7075965 DOI: 10.1038/s41598-020-61657-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/24/2020] [Indexed: 11/09/2022] Open
Abstract
We consider the ground state and the collective excitations of dipolar Bose-Einstein condensates in a bubble trap, i.e., a shell-shaped spherically symmetric confining potential. By means of an appropriate Gaussian ansatz, we determine the ground-state properties in the case where the particles interact by means of both the isotropic and short-range contact and the anisotropic and long-range dipole-dipole potential in the thin-shell limit. Moreover, with the ground state at hand, we employ the sum-rule approach to study the monopole, the two-, the three-dimensional quadrupole as well as the dipole modes. We find situations in which neither the virial nor Kohn's theorem can be applied. On top of that, we demonstrate the existence of anisotropic particle density profiles, which are absent in the case with repulsive contact interaction only. These significant deviations from what one would typically expect are then traced back to both the anisotropic nature of the dipolar interaction and the novel topology introduced by the bubble trap.
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Affiliation(s)
- Pedro C Diniz
- São Carlos Institute of Physics, University of São Paulo, PO Box 369, 13560-970, São Carlos, SP, Brazil
| | - Eduardo A B Oliveira
- São Carlos Institute of Physics, University of São Paulo, PO Box 369, 13560-970, São Carlos, SP, Brazil
| | - Aristeu R P Lima
- Universidade da Integração Internacional da Lusofonia Afro-Brasileira, Campus das Auroras, Acarape-Ceará, Brazil.
| | - Emanuel A L Henn
- São Carlos Institute of Physics, University of São Paulo, PO Box 369, 13560-970, São Carlos, SP, Brazil.
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16
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Thomas R, Kjærgaard N. A digital feedback controller for stabilizing large electric currents to the ppm level for Feshbach resonance studies. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:034705. [PMID: 32260003 DOI: 10.1063/1.5128935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 02/23/2020] [Indexed: 06/11/2023]
Abstract
Magnetic Feshbach resonances are a key tool in the field of ultracold quantum gases, but their full exploitation requires the generation of large, stable magnetic fields up to 1000 G with fractional stabilities of better than 10-4. Design considerations for electromagnets producing these fields, such as optical access and fast dynamical response, mean that electric currents in excess of 100 A are often needed to obtain the requisite field strengths. We describe a simple digital proportional-integral-derivative current controller constructed using a field-programmable gate array and off-the-shelf evaluation boards that allows for gain scheduling, enabling optimal control of current sources with non-linear actuators. Our controller can stabilize an electric current of 337.5 A to the level of 7.5 × 10-7 in an averaging time of 10 min and with a control bandwidth of 2 kHz.
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Affiliation(s)
- R Thomas
- Department of Physics, QSO-Centre for Quantum Science, and Dodd-Walls Centre, University of Otago, Dunedin 9016, New Zealand
| | - N Kjærgaard
- Department of Physics, QSO-Centre for Quantum Science, and Dodd-Walls Centre, University of Otago, Dunedin 9016, New Zealand
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17
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Van Loon S, Tempere J, Kurkjian H. Beyond Mean-Field Corrections to the Quasiparticle Spectrum of Superfluid Fermi Gases. PHYSICAL REVIEW LETTERS 2020; 124:073404. [PMID: 32142351 DOI: 10.1103/physrevlett.124.073404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 12/02/2019] [Accepted: 01/21/2020] [Indexed: 06/10/2023]
Abstract
We investigate the fermionic quasiparticle branch of superfluid Fermi gases in the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation (BEC) crossover and calculate the quasiparticle lifetime and energy shift due to its coupling with the collective mode. The only close-to-resonance process that low-energy quasiparticles can undergo at zero temperature is the emission of a bosonic excitation from the phononic branch. Close to the minimum of the branch we find that the quasiparticles remain undamped, allowing us to compute corrections to experimentally relevant quantities such as the energy gap, location of the minimum, effective mass, and Landau critical velocity.
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Affiliation(s)
- Senne Van Loon
- TQC, Universiteit Antwerpen, Universiteitsplein 1, B-2610 Antwerpen, België
| | - Jacques Tempere
- TQC, Universiteit Antwerpen, Universiteitsplein 1, B-2610 Antwerpen, België
| | - Hadrien Kurkjian
- TQC, Universiteit Antwerpen, Universiteitsplein 1, B-2610 Antwerpen, België
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18
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Tobias WG, Matsuda K, Valtolina G, De Marco L, Li JR, Ye J. Thermalization and Sub-Poissonian Density Fluctuations in a Degenerate Molecular Fermi Gas. PHYSICAL REVIEW LETTERS 2020; 124:033401. [PMID: 32031827 DOI: 10.1103/physrevlett.124.033401] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Indexed: 06/10/2023]
Abstract
We observe thermalization in the production of a degenerate Fermi gas of polar ^{40}K^{87}Rb molecules. By measuring the atom-dimer elastic scattering cross section near the Feshbach resonance, we show that Feshbach molecules rapidly reach thermal equilibrium with both parent atomic species. Equilibrium is essentially maintained through coherent transfer to the ground state. Sub-Poissonian density fluctuations in Feshbach and ground-state molecules are measured, giving an independent characterization of degeneracy and directly probing the molecular Fermi-Dirac distribution.
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Affiliation(s)
- William G Tobias
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Kyle Matsuda
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Giacomo Valtolina
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Luigi De Marco
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Jun-Ru Li
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
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19
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Oscillatory-like expansion of a Fermionic superfluid. Sci Bull (Beijing) 2020; 65:7-11. [PMID: 36659071 DOI: 10.1016/j.scib.2019.10.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/25/2019] [Accepted: 10/14/2019] [Indexed: 01/21/2023]
Abstract
We study the expansion behaviors of a Fermionic superfluid in a cigar-shaped optical dipole trap for the whole BEC-BCS crossover and various temperatures. At low temperature (0.06(1)TF), the atom cloud undergoes an anisotropic hydrodynamic expansion over 30 ms, which behaves like oscillation in the horizontal plane. By analyzing the expansion dynamics according to the superfluid hydrodynamic equation, the effective polytropic index γ¯ of Equation-of-State (EoS) of Fermionic superfluid is extracted. The γ¯ values show a non-monotonic behavior over the BEC-BCS crossover, and have a good agreement with the theoretical results in the unitarity and BEC side. The normalized quasi-frequencies of the oscillatory expansion are measured, which drop significantly from the BEC side to the BCS side and reach a minimum value of 1.73 around 1/kFa=-0.25. Our work improves the understanding of the dynamic properties of strongly interacting Fermi gas.
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20
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Schlawin F, Jaksch D. Cavity-Mediated Unconventional Pairing in Ultracold Fermionic Atoms. PHYSICAL REVIEW LETTERS 2019; 123:133601. [PMID: 31697538 DOI: 10.1103/physrevlett.123.133601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Indexed: 06/10/2023]
Abstract
We investigate long-range pairing interactions between ultracold fermionic atoms confined in an optical lattice which are mediated by the coupling to a cavity. In the absence of other perturbations, we find three degenerate pairing symmetries for a two-dimensional square lattice. By tuning a weak local atomic interaction via a Feshbach resonance or by tuning a weak magnetic field, the superfluid system can be driven from a topologically trivial s wave to topologically ordered, chiral superfluids containing Majorana edge states. Our work points out a novel path towards the creation of exotic superfluid states by exploiting the competition between long-range and short-range interactions.
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Affiliation(s)
- Frank Schlawin
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Dieter Jaksch
- Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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21
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Collisions between cold molecules in a superconducting magnetic trap. Nature 2019; 572:189-193. [DOI: 10.1038/s41586-019-1446-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 06/12/2019] [Indexed: 11/08/2022]
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22
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Sompet P, Szigeti SS, Schwartz E, Bradley AS, Andersen MF. Thermally robust spin correlations between two 85Rb atoms in an optical microtrap. Nat Commun 2019; 10:1889. [PMID: 31015406 PMCID: PMC6478867 DOI: 10.1038/s41467-019-09420-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 03/11/2019] [Indexed: 11/21/2022] Open
Abstract
The complex collisional properties of atoms fundamentally limit investigations into a range of processes in many-atom ensembles. In contrast, the bottom-up assembly of few- and many-body systems from individual atoms offers a controlled approach to isolating and studying such collisional processes. Here, we use optical tweezers to individually assemble pairs of trapped 85Rb atoms, and study the spin dynamics of the two-body system in a thermal state. The spin-2 atoms show strong pair correlation between magnetic sublevels on timescales exceeding one second, with measured relative number fluctuations 11.9 ± 0.3 dB below quantum shot noise, limited only by detection efficiency. Spin populations display relaxation dynamics consistent with simulations and theoretical predictions for 85Rb spin interactions, and contrary to the coherent spin waves witnessed in finite-temperature many-body experiments and zero-temperature two-body experiments. Our experimental approach offers a versatile platform for studying two-body quantum dynamics and may provide a route to thermally robust entanglement generation. Spin-changing atomic collisions are important for thermally robust entanglement generation with applications in quantum information. Here the authors demonstrate record high spin state correlations and long spin relaxation times in the collision of two Rb atoms at relatively warm temperatures.
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Affiliation(s)
- Pimonpan Sompet
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Otago, Dunedin, New Zealand.,Max-Planck-Institut für Quantenoptik, 85748, Garching, Germany
| | - Stuart S Szigeti
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Otago, Dunedin, New Zealand.,Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Canberra, ACT, 2601, Australia
| | - Eyal Schwartz
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Otago, Dunedin, New Zealand
| | - Ashton S Bradley
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Otago, Dunedin, New Zealand
| | - Mikkel F Andersen
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Otago, Dunedin, New Zealand.
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23
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Navadeh-Toupchi M, Takemura N, Anderson MD, Oberli DY, Portella-Oberli MT. Polaritonic Cross Feshbach Resonance. PHYSICAL REVIEW LETTERS 2019; 122:047402. [PMID: 30768331 DOI: 10.1103/physrevlett.122.047402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 10/22/2018] [Indexed: 06/09/2023]
Abstract
We demonstrate the existence of a cross Feshbach resonance by strongly driving a lower polariton mode and by monitoring in time the transmission of a short optical pulse at the energy of the upper polariton mode in a semiconductor microcavity. From the signatures of the optical resonance, strength, and sign of the energy shift, we attribute the origin of the scattering process between polariton modes with opposite circular polarization to a biexciton bound state. From this study, we infer the conditions required for a strong enhancement of the generation of entangled photon pairs.
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Affiliation(s)
- M Navadeh-Toupchi
- Institute of Physics, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - N Takemura
- Institute of Physics, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - M D Anderson
- Institute of Physics, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - D Y Oberli
- Institute of Physics, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - M T Portella-Oberli
- Institute of Physics, School of Basic Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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24
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De Marco L, Valtolina G, Matsuda K, Tobias WG, Covey JP, Ye J. A degenerate Fermi gas of polar molecules. Science 2019; 363:853-856. [PMID: 30655445 DOI: 10.1126/science.aau7230] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 01/04/2019] [Indexed: 11/02/2022]
Abstract
Experimental realization of a quantum degenerate gas of molecules would provide access to a wide range of phenomena in molecular and quantum sciences. However, the very complexity that makes ultracold molecules so enticing has made reaching degeneracy an outstanding experimental challenge over the past decade. We now report the production of a degenerate Fermi gas of ultracold polar molecules of potassium-rubidium. Through coherent adiabatic association in a deeply degenerate mixture of a rubidium Bose-Einstein condensate and a potassium Fermi gas, we produce molecules at temperatures below 0.3 times the Fermi temperature. We explore the properties of this reactive gas and demonstrate how degeneracy suppresses chemical reactions, making a long-lived degenerate gas of polar molecules a reality.
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Affiliation(s)
- Luigi De Marco
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado, Boulder, CO 80309, USA.,Department of Physics, University of Colorado, 440 UCB, Boulder, CO 80309, USA
| | - Giacomo Valtolina
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado, Boulder, CO 80309, USA.,Department of Physics, University of Colorado, 440 UCB, Boulder, CO 80309, USA
| | - Kyle Matsuda
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado, Boulder, CO 80309, USA.,Department of Physics, University of Colorado, 440 UCB, Boulder, CO 80309, USA
| | - William G Tobias
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado, Boulder, CO 80309, USA.,Department of Physics, University of Colorado, 440 UCB, Boulder, CO 80309, USA
| | - Jacob P Covey
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado, Boulder, CO 80309, USA.,Department of Physics, University of Colorado, 440 UCB, Boulder, CO 80309, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology (NIST) and University of Colorado, Boulder, CO 80309, USA. .,Department of Physics, University of Colorado, 440 UCB, Boulder, CO 80309, USA
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25
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Park JW, Ko B, Shin Y. Critical Vortex Shedding in a Strongly Interacting Fermionic Superfluid. PHYSICAL REVIEW LETTERS 2018; 121:225301. [PMID: 30547641 DOI: 10.1103/physrevlett.121.225301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Indexed: 06/09/2023]
Abstract
We study the critical vortex shedding in a strongly interacting fermionic superfluid of ^{6}Li across the BEC-BCS crossover. By moving an optical obstacle in the sample and directly imaging the vortices after the time of flight, the critical velocity u_{vor} for vortex shedding is measured as a function of the obstacle travel distance L. The observed u_{vor} increases with decreasing L, where the rate of increase is the highest in the unitary regime. In the deep Bose-Einstein condensation regime, an empirical dissipation model well captures the dependence of u_{vor} on L, characterized by a constant value of η=-[d(1/u_{vor})/d(1/L)]. However, as the system is tuned across the resonance, a step increase of η develops about a characteristic distance L_{c} as L is increased, where L_{c} is comparable to the obstacle size. This bimodal behavior is strengthened as the system is tuned towards the BCS regime. We attribute this evolution of u_{vor} to the emergence of the underlying fermionic degree of freedom in the vortex-shedding dynamics of a Fermi condensate.
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Affiliation(s)
- Jee Woo Park
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
| | - Bumsuk Ko
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Korea
| | - Y Shin
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Korea
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26
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Gänger B, Phieler J, Nagler B, Widera A. A versatile apparatus for fermionic lithium quantum gases based on an interference-filter laser system. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:093105. [PMID: 30278689 DOI: 10.1063/1.5045827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 08/25/2018] [Indexed: 06/08/2023]
Abstract
We report on the design and construction of a versatile setup for experiments with ultracold lithium (Li) gases. We discuss our methods to prepare an atomic beam and laser cool it in a Zeeman slower and a subsequent magneto-optical trap, which rely on established methods. We focus on our laser system based on a stable interference-filter-stabilized, linear-extended-cavity diode laser, so far unreported for lithium wavelengths. Moreover, we describe our optical setup to combine various laser frequencies for cooling, manipulation, and detection of Li atoms. We characterize the performance of our system preparing degenerate samples of Li atoms via forced evaporation in a hybrid crossed-beam optical-dipole trap plus confining magnetic trap. Our apparatus allows one to produce quantum gases of N ≈ 105…106 fermionic lithium-6 atoms at nanokelvin temperatures in cycle times below 10 s. Our optical system is particularly suited to study the dynamics of fermionic superfluids in engineered optical potentials.
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Affiliation(s)
- Benjamin Gänger
- Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Jan Phieler
- Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Benjamin Nagler
- Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Artur Widera
- Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
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27
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Shkedrov C, Florshaim Y, Ness G, Gandman A, Sagi Y. High-Sensitivity rf Spectroscopy of a Strongly Interacting Fermi Gas. PHYSICAL REVIEW LETTERS 2018; 121:093402. [PMID: 30230882 DOI: 10.1103/physrevlett.121.093402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 06/25/2018] [Indexed: 06/08/2023]
Abstract
rf spectroscopy is one of the most powerful probing techniques in the field of ultracold gases. We report on a novel rf spectroscopy scheme with which we can detect very weak signals of only a few atoms. Using this method, we extended the experimentally accessible photon-energies range by an order of magnitude compared to previous studies. We directly verify a universal property of fermions with short-range interactions which is a power-law scaling of the rf spectrum tail all the way up to the interaction scale. We also determine, with high precision, the trap average contact parameter for different interaction strength. Finally, we employ our technique to precisely measure the binding energy of Feshbach molecules in an extended range of magnetic fields. These data are used to extract a new calibration of the Feshbach resonance between the two lowest energy levels of ^{40}K.
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Affiliation(s)
- Constantine Shkedrov
- Physics Department, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Yanay Florshaim
- Physics Department, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Gal Ness
- Physics Department, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Andrey Gandman
- Physics Department, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Yoav Sagi
- Physics Department, Technion-Israel Institute of Technology, Haifa 32000, Israel
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28
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Tennyson J, McKemmish LK, Rivlin T. Low-temperature chemistry using the R-matrix method. Faraday Discuss 2018; 195:31-48. [PMID: 27711838 DOI: 10.1039/c6fd00110f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Techniques for producing cold and ultracold molecules are enabling the study of chemical reactions and scattering at the quantum scattering limit, with only a few partial waves contributing to the incident channel, leading to the observation and even full control of state-to-state collisions in this regime. A new R-matrix formalism is presented for tackling problems involving low- and ultra-low energy collisions. This general formalism is particularly appropriate for slow collisions occurring on potential energy surfaces with deep wells. The many resonance states make such systems hard to treat theoretically but offer the best prospects for novel physics: resonances are already being widely used to control diatomic systems and should provide the route to steering ultracold reactions. Our R-matrix-based formalism builds on the progress made in variational calculations of molecular spectra by using these methods to provide wavefunctions for the whole system at short internuclear distances, (a regime known as the inner region). These wavefunctions are used to construct collision energy-dependent R-matrices which can then be propagated to give cross sections at each collision energy. The method is formulated for ultracold collision systems with differing numbers of atoms.
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Affiliation(s)
- Jonathan Tennyson
- Department of Physics and Astronomy, University College London, London WC1E 6BT, UK.
| | - Laura K McKemmish
- Department of Physics and Astronomy, University College London, London WC1E 6BT, UK.
| | - Tom Rivlin
- Department of Physics and Astronomy, University College London, London WC1E 6BT, UK.
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Thomas O, Lippe C, Eichert T, Ott H. Experimental realization of a Rydberg optical Feshbach resonance in a quantum many-body system. Nat Commun 2018; 9:2238. [PMID: 29884824 PMCID: PMC5993778 DOI: 10.1038/s41467-018-04684-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 05/10/2018] [Indexed: 11/08/2022] Open
Abstract
Feshbach resonances are a powerful tool to tune the interaction in an ultracold atomic gas. The commonly used magnetic Feshbach resonances are specific for each species and are restricted with respect to their temporal and spatial modulation. Optical Feshbach resonances are an alternative which can overcome this limitation. Here, we show that ultra-long-range Rydberg molecules can be used to implement an optical Feshbach resonance. Tuning the on-site interaction of a degenerate Bose gas in a 3D optical lattice, we demonstrate a similar performance compared to recent realizations of optical Feshbach resonances using intercombination transitions. Our results open up a class of optical Feshbach resonances with a plenitude of available lines for many atomic species and the possibility to further increase the performance by carefully selecting the underlying Rydberg state.
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Affiliation(s)
- O Thomas
- Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, Erwin-Schrödinger-Straße 46, 67663, Kaiserslautern, Germany
- Graduate School Materials Science in Mainz, Staudinger Weg 9, 55128, Mainz, Germany
| | - C Lippe
- Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, Erwin-Schrödinger-Straße 46, 67663, Kaiserslautern, Germany
| | - T Eichert
- Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, Erwin-Schrödinger-Straße 46, 67663, Kaiserslautern, Germany
| | - H Ott
- Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, Erwin-Schrödinger-Straße 46, 67663, Kaiserslautern, Germany.
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30
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Li Z, Gong T, Ji Z, Zhao Y, Xiao L, Jia S. A dynamical process of optically trapped singlet ground state 85Rb 133Cs molecules produced via short-range photoassociation. Phys Chem Chem Phys 2018; 20:4893-4900. [PMID: 29384158 DOI: 10.1039/c7cp07756d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We investigate the dynamical process of optically trapped X1Σ+ (v'' = 0) state 85Rb133Cs molecules distributed in J'' = 1 and J'' = 3 rotational states. The considered molecules, formed from short-range photoassociation of mixed cold atoms, are subsequently confined in a crossed optical dipole trap. Based on a phenomenological rate equation, we provide a detailed study of the dynamics of 85Rb133Cs molecules during the loading and holding processes. The inelastic collisions of 85Rb133Cs molecules in the X1Σ+ (v'' = 0, J'' = 1 and J'' = 3) states with ultracold 85Rb (or 133Cs) atoms are measured to be 1.0 (2) × 10-10 cm3 s-1 (1.2 (3) × 10-10 cm3 s-1). Our work provides a simple and generic procedure for studying the dynamical process of trapped cold molecules in the singlet ground states.
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Affiliation(s)
- Zhonghao Li
- Shanxi University, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Wucheng Rd. 92, 030006 Taiyuan, China.
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He L, Hu H, Liu XJ. Realizing Fulde-Ferrell Superfluids via a Dark-State Control of Feshbach Resonances. PHYSICAL REVIEW LETTERS 2018; 120:045302. [PMID: 29437455 DOI: 10.1103/physrevlett.120.045302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Indexed: 06/08/2023]
Abstract
We propose that the long-sought Fulde-Ferrell superfluidity with nonzero momentum pairing can be realized in ultracold two-component Fermi gases of ^{40}K or ^{6}Li atoms by optically tuning their magnetic Feshbach resonances via the creation of a closed-channel dark state with a Doppler-shifted Stark effect. In this scheme, two counterpropagating optical fields are applied to couple two molecular states in the closed channel to an excited molecular state, leading to a significant violation of Galilean invariance in the dark-state regime and hence to the possibility of Fulde-Ferrell superfluidity. We develop a field theoretical formulation for both two-body and many-body problems and predict that the Fulde-Ferrell state has remarkable properties, such as anisotropic single-particle dispersion relation, suppressed superfluid density at zero temperature, anisotropic sound velocity, and rotonic collective mode. The latter two features can be experimentally probed using Bragg spectroscopy, providing a smoking-gun proof of Fulde-Ferrell superfluidity.
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Affiliation(s)
- Lianyi He
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Hui Hu
- Centre for Quantum and Optical Science, Swinburne University of Technology, Melbourne 3122, Australia
| | - Xia-Ji Liu
- Centre for Quantum and Optical Science, Swinburne University of Technology, Melbourne 3122, Australia
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32
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Matzliah N, Edri H, Sinay A, Ozeri R, Davidson N. Observation of Optomechanical Strain in a Cold Atomic Cloud. PHYSICAL REVIEW LETTERS 2017; 119:163201. [PMID: 29099207 DOI: 10.1103/physrevlett.119.163201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Indexed: 06/07/2023]
Abstract
We report the observation of optomechanical strain applied to thermal and quantum degenerate ^{87}Rb atomic clouds when illuminated by an intense, far detuned homogeneous laser beam. In this regime the atomic cloud acts as a lens that focuses the laser beam. As a backaction, the atoms experience a force opposite to the beam deflection, which depends on the atomic cloud density profile. We experimentally demonstrate the basic features of this force, distinguishing it from the well-established scattering and dipole forces. The observed strain saturates, ultimately limiting the momentum impulse that can be transferred to the atoms. This optomechanical force may effectively induce interparticle interactions, which can be optically tuned.
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Affiliation(s)
- Noam Matzliah
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Hagai Edri
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Asif Sinay
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Roee Ozeri
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Nir Davidson
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
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33
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Mueller EJ. Review of pseudogaps in strongly interacting Fermi gases. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:104401. [PMID: 28686169 DOI: 10.1088/1361-6633/aa7e53] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A central challenge in modern condensed matter physics is developing the tools for understanding nontrivial yet unordered states of matter. One important idea to emerge in this context is that of a 'pseudogap': the fact that under appropriate circumstances the normal state displays a suppression of the single particle spectral density near the Fermi level, reminiscent of the gaps seen in ordered states of matter. While these concepts arose in a solid state context, they are now being explored in cold gases. This article reviews the current experimental and theoretical understanding of the normal state of strongly interacting Fermi gases, with particular focus on the phenomonology which is traditionally associated with the pseudogap.
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Affiliation(s)
- Erich J Mueller
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca NY 14853, United States of America
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35
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Balakrishnan N. Perspective: Ultracold molecules and the dawn of cold controlled chemistry. J Chem Phys 2016; 145:150901. [DOI: 10.1063/1.4964096] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- N. Balakrishnan
- Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154, USA
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37
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Yao YQ, Li J, Han W, Wang DS, Liu WM. Localized spatially nonlinear matter waves in atomic-molecular Bose-Einstein condensates with space-modulated nonlinearity. Sci Rep 2016; 6:29566. [PMID: 27403634 PMCID: PMC4941720 DOI: 10.1038/srep29566] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/17/2016] [Indexed: 11/17/2022] Open
Abstract
The intrinsic nonlinearity is the most remarkable characteristic of the Bose-Einstein condensates (BECs) systems. Many studies have been done on atomic BECs with time- and space- modulated nonlinearities, while there is few work considering the atomic-molecular BECs with space-modulated nonlinearities. Here, we obtain two kinds of Jacobi elliptic solutions and a family of rational solutions of the atomic-molecular BECs with trapping potential and space-modulated nonlinearity and consider the effect of three-body interaction on the localized matter wave solutions. The topological properties of the localized nonlinear matter wave for no coupling are analysed: the parity of nonlinear matter wave functions depends only on the principal quantum number n, and the numbers of the density packets for each quantum state depend on both the principal quantum number n and the secondary quantum number l. When the coupling is not zero, the localized nonlinear matter waves given by the rational function, their topological properties are independent of the principal quantum number n, only depend on the secondary quantum number l. The Raman detuning and the chemical potential can change the number and the shape of the density packets. The stability of the Jacobi elliptic solutions depends on the principal quantum number n, while the stability of the rational solutions depends on the chemical potential and Raman detuning.
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Affiliation(s)
- Yu-Qin Yao
- Department of Applied Mathematics, China Agricultural University, Beijing 100083, People’s Republic of China
| | - Ji Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Wei Han
- Key Laboratory of Time and Frequency Primary Standards, National Time Service Center, Chinese Academy of Sciences, Xian 710600, People’s Republic of China
| | - Deng-Shan Wang
- School of Science, Beijing Information Science and Technology University, Beijing 100192, People’s Republic of China
| | - Wu-Ming Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
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38
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High-pressure Gas Activation for Amorphous Indium-Gallium-Zinc-Oxide Thin-Film Transistors at 100 °C. Sci Rep 2016; 6:23039. [PMID: 26972476 PMCID: PMC4789782 DOI: 10.1038/srep23039] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 02/23/2016] [Indexed: 02/03/2023] Open
Abstract
We investigated the use of high-pressure gases as an activation energy source for
amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistors (TFTs).
High-pressure annealing (HPA) in nitrogen (N2) and oxygen (O2)
gases was applied to activate a-IGZO TFTs at 100 °C at
pressures in the range from 0.5 to 4 MPa. Activation of the a-IGZO TFTs
during HPA is attributed to the effect of the high-pressure environment, so that the
activation energy is supplied from the kinetic energy of the gas molecules. We
reduced the activation temperature from 300 °C to
100 °C via the use of HPA. The electrical characteristics of
a-IGZO TFTs annealed in O2 at 2 MPa were superior to those
annealed in N2 at 4 MPa, despite the lower pressure. For
O2 HPA under 2 MPa at 100 °C, the
field effect mobility and the threshold voltage shift under positive bias stress
were improved by 9.00 to 10.58 cm2/V.s and 3.89 to
2.64 V, respectively. This is attributed to not only the effects of the
pressurizing effect but also the metal-oxide construction effect which assists to
facilitate the formation of channel layer and reduces oxygen vacancies, served as
electron trap sites.
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39
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ElOualhazi R, Berriche H. Electronic Structure and Spectra of the MgLi+ Ionic Molecule. J Phys Chem A 2016; 120:452-65. [DOI: 10.1021/acs.jpca.5b10209] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R. ElOualhazi
- Laboratory
of Interfaces and Advanced Materials, Faculty of Science, University of Monastir, 5019 Monastir, Tunisia
| | - H. Berriche
- Laboratory
of Interfaces and Advanced Materials, Faculty of Science, University of Monastir, 5019 Monastir, Tunisia
- Department
of Mathematics and Natural Sciences, School of Arts and Sciences, American University of Ras Al Khaimah, RAK, P.O. Box 10021, UAE
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40
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Genkina D, Aycock LM, Stuhl BK, Lu HI, Williams RA, Spielman IB. Feshbach enhanced s-wave scattering of fermions: direct observation with optimized absorption imaging. NEW JOURNAL OF PHYSICS 2016; 18:013001. [PMID: 26903778 PMCID: PMC4759653 DOI: 10.1088/1367-2630/18/1/013001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We directly measured the normalized s-wave scattering cross-section of ultracold 40K atoms across a magnetic-field Feshbach resonance by colliding pairs of degenerate Fermi gases (DFGs) and imaging the scattered atoms. We extracted the scattered fraction for a range of bias magnetic fields, and measured the resonance location to be B0 = 20.206(15) mT with width Δ = 1.0(5) mT. To optimize the signal-to-noise ratio of atom number in scattering images, we developed techniques to interpret absorption images in a regime where recoil induced detuning corrections are significant. These imaging techniques are generally applicable to experiments with lighter alkalis that would benefit from maximizing signal-to-noise ratio on atom number counting at the expense of spatial imaging resolution.
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Affiliation(s)
- D Genkina
- Joint Quantum Institute, National Institute of Standards and Technology, and University of Maryland, Gaithersburg, MD, 20899 USA
| | - LM Aycock
- Joint Quantum Institute, National Institute of Standards and Technology, and University of Maryland, Gaithersburg, MD, 20899 USA
- Physics Department, Cornell University, Ithaca, NY 14850 USA
| | - BK Stuhl
- Joint Quantum Institute, National Institute of Standards and Technology, and University of Maryland, Gaithersburg, MD, 20899 USA
| | - H-I Lu
- Joint Quantum Institute, National Institute of Standards and Technology, and University of Maryland, Gaithersburg, MD, 20899 USA
| | - RA Williams
- National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW, UK
| | - IB Spielman
- Joint Quantum Institute, National Institute of Standards and Technology, and University of Maryland, Gaithersburg, MD, 20899 USA
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42
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Pagano G, Mancini M, Cappellini G, Livi L, Sias C, Catani J, Inguscio M, Fallani L. Strongly Interacting Gas of Two-Electron Fermions at an Orbital Feshbach Resonance. PHYSICAL REVIEW LETTERS 2015; 115:265301. [PMID: 26764999 DOI: 10.1103/physrevlett.115.265301] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Indexed: 06/05/2023]
Abstract
We report on the experimental observation of a strongly interacting gas of ultracold two-electron fermions with an orbital degree of freedom and magnetically tunable interactions. This realization has been enabled by the demonstration of a novel kind of Feshbach resonance occurring in the scattering of two (173)Yb atoms in different nuclear and electronic states. The strongly interacting regime at resonance is evidenced by the observation of anisotropic hydrodynamic expansion of the two-orbital Fermi gas. These results pave the way towards the realization of new quantum states of matter with strongly correlated fermions with an orbital degree of freedom.
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Affiliation(s)
- G Pagano
- Department of Physics and Astronomy, University of Florence, I-50019 Sesto Fiorentino, Italy
| | - M Mancini
- Department of Physics and Astronomy, University of Florence, I-50019 Sesto Fiorentino, Italy
| | - G Cappellini
- LENS European Laboratory for Nonlinear Spectroscopy, I-50019 Sesto Fiorentino, Italy
| | - L Livi
- LENS European Laboratory for Nonlinear Spectroscopy, I-50019 Sesto Fiorentino, Italy
| | - C Sias
- LENS European Laboratory for Nonlinear Spectroscopy, I-50019 Sesto Fiorentino, Italy
- INRIM Istituto Nazionale di Ricerca Metrologica, I-10135 Torino, Italy
| | - J Catani
- LENS European Laboratory for Nonlinear Spectroscopy, I-50019 Sesto Fiorentino, Italy
- INO-CNR Istituto Nazionale di Ottica del CNR, Sezione di Sesto Fiorentino, I-50019 Sesto Fiorentino, Italy
- INFN Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, I-50019 Sesto Fiorentino, Italy
| | - M Inguscio
- Department of Physics and Astronomy, University of Florence, I-50019 Sesto Fiorentino, Italy
- LENS European Laboratory for Nonlinear Spectroscopy, I-50019 Sesto Fiorentino, Italy
- INRIM Istituto Nazionale di Ricerca Metrologica, I-10135 Torino, Italy
| | - L Fallani
- Department of Physics and Astronomy, University of Florence, I-50019 Sesto Fiorentino, Italy
- LENS European Laboratory for Nonlinear Spectroscopy, I-50019 Sesto Fiorentino, Italy
- INFN Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, I-50019 Sesto Fiorentino, Italy
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43
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Frisch A, Mark M, Aikawa K, Baier S, Grimm R, Petrov A, Kotochigova S, Quéméner G, Lepers M, Dulieu O, Ferlaino F. Ultracold Dipolar Molecules Composed of Strongly Magnetic Atoms. PHYSICAL REVIEW LETTERS 2015; 115:203201. [PMID: 26613437 DOI: 10.1103/physrevlett.115.203201] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Indexed: 06/05/2023]
Abstract
In a combined experimental and theoretical effort, we demonstrate a novel type of dipolar system made of ultracold bosonic dipolar molecules with large magnetic dipole moments. Our dipolar molecules are formed in weakly bound Feshbach molecular states from a sample of strongly magnetic bosonic erbium atoms. We show that the ultracold magnetic molecules can carry very large dipole moments and we demonstrate how to create and characterize them, and how to change their orientation. Finally, we confirm that the relaxation rates of molecules in a quasi-two-dimensional geometry can be reduced by using the anisotropy of the dipole-dipole interaction and that this reduction follows a universal dipolar behavior.
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Affiliation(s)
- A Frisch
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria
| | - M Mark
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - K Aikawa
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - S Baier
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - R Grimm
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria
| | - A Petrov
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - S Kotochigova
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - G Quéméner
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, 91405 Orsay, France
| | - M Lepers
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, 91405 Orsay, France
| | - O Dulieu
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, 91405 Orsay, France
| | - F Ferlaino
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria
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44
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Setiawan F, Sengupta K, Spielman IB, Sau JD. Dynamical Detection of Topological Phase Transitions in Short-Lived Atomic Systems. PHYSICAL REVIEW LETTERS 2015; 115:190401. [PMID: 26588362 DOI: 10.1103/physrevlett.115.190401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Indexed: 06/05/2023]
Abstract
We demonstrate that dynamical probes provide direct means of detecting the topological phase transition (TPT) between conventional and topological phases, which would otherwise be difficult to access because of loss or heating processes. We propose to avoid such heating by rapidly quenching in and out of the short-lived topological phase across the transition that supports gapless excitations. Following the quench, the distribution of excitations in the final conventional phase carries signatures of the TPT. We apply this strategy to study the TPT into a Majorana-carrying topological phase predicted in one-dimensional spin-orbit-coupled Fermi gases with attractive interactions. The resulting spin-resolved momentum distribution, computed by self-consistently solving the time-dependent Bogoliubov-de Gennes equations, exhibits Kibble-Zurek scaling and Stückelberg oscillations characteristic of the TPT. We discuss parameter regimes where the TPT is experimentally accessible.
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Affiliation(s)
- F Setiawan
- Department of Physics, Condensed Matter Theory Center and Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
| | - K Sengupta
- Theoretical Physics Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - I B Spielman
- Joint Quantum Institute, National Institute of Standards and Technology, and University of Maryland, Gaithersburg, Maryland 20899, USA
| | - Jay D Sau
- Department of Physics, Condensed Matter Theory Center and Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
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45
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El-Sherbini TM. Advances in atomic physics: Four decades of contribution of the Cairo University - Atomic Physics Group. J Adv Res 2015; 6:643-61. [PMID: 26425356 PMCID: PMC4563599 DOI: 10.1016/j.jare.2013.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Revised: 08/19/2013] [Accepted: 08/19/2013] [Indexed: 11/24/2022] Open
Abstract
In this review article, important developments in the field of atomic physics are highlighted and linked to research works the author was involved in himself as a leader of the Cairo University - Atomic Physics Group. Starting from the late 1960s - when the author first engaged in research - an overview is provided of the milestones in the fascinating landscape of atomic physics.
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46
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de Forges de Parny L, Rousseau VG, Roscilde T. Feshbach-stabilized insulator of bosons in optical lattices. PHYSICAL REVIEW LETTERS 2015; 114:195302. [PMID: 26024178 DOI: 10.1103/physrevlett.114.195302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Indexed: 06/04/2023]
Abstract
Feshbach resonances-namely, resonances between an unbound two-body (atomic) state and a bound (molecular) state, differing in magnetic moment-are a unique tool to tune the interaction properties of ultracold atoms. Here we show that the spin-changing interactions, coherently coupling the atomic and molecular states, can act as a novel mechanism to stabilize an insulating phase-the Feshbach insulator-for bosons in an optical lattice close to a narrow Feshbach resonance. Making use of quantum Monte Carlo simulations and mean-field theory, we show that the Feshbach insulator appears around the resonance, preventing the system from collapsing when the effective atomic scattering length becomes negative. On the atomic side of the resonance, the transition from condensate to Feshbach insulator has a characteristic first-order nature, due to the simultaneous loss of coherence in the atomic and molecular components. These features appear clearly in the ground-state phase diagram of, e.g., ^{87}Rb around its 414 G resonance, and they are therefore directly amenable to experimental observation.
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Affiliation(s)
- L de Forges de Parny
- Laboratoire de Physique, CNRS UMR 5672, École Normale Supérieure de Lyon, Université de Lyon, 46 Allée d'Italie, F-69364 Lyon, France
| | - V G Rousseau
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - T Roscilde
- Laboratoire de Physique, CNRS UMR 5672, École Normale Supérieure de Lyon, Université de Lyon, 46 Allée d'Italie, F-69364 Lyon, France
- Institut Universitaire de France, 103 boulevard Saint-Michel, 75005 Paris, France
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47
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Affiliation(s)
- Artur Widera
- Physics Department and State Research Center, Kaiserslautern University, 67663 Kaiserslautern, Germany.
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48
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Gou D, Kuang X, Gao Y, Huo D. Theoretical study on the ground state of the polar alkali-metal-barium molecules: potential energy curve and permanent dipole moment. J Chem Phys 2015; 142:034308. [PMID: 25612710 DOI: 10.1063/1.4906049] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In this paper, we systematically investigate the electronic structure for the (2)Σ(+) ground state of the polar alkali-metal-alkaline-earth-metal molecules BaAlk (Alk = Li, Na, K, Rb, and Cs). Potential energy curves and permanent dipole moments (PDMs) are determined using power quantum chemistry complete active space self-consistent field and multi-reference configuration interaction methods. Basic spectroscopic constants are derived from ro-vibrational bound state calculation. From the calculations, it is shown that BaK, BaRb, and BaCs molecules have moderate values of PDM at the equilibrium bond distance (BaK:1.62 D, BaRb:3.32 D, and BaCs:4.02 D). Besides, the equilibrium bond length (4.93 Å and 5.19 Å) and dissociation energy (0.1825 eV and 0.1817 eV) for the BaRb and BaCs are also obtained.
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Affiliation(s)
- Dezhi Gou
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
| | - Xiaoyu Kuang
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
| | - Yufeng Gao
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
| | - Dongming Huo
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
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Goldman N, Juzeliūnas G, Öhberg P, Spielman IB. Light-induced gauge fields for ultracold atoms. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2014; 77:126401. [PMID: 25422950 DOI: 10.1088/0034-4885/77/12/126401] [Citation(s) in RCA: 181] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Gauge fields are central in our modern understanding of physics at all scales. At the highest energy scales known, the microscopic universe is governed by particles interacting with each other through the exchange of gauge bosons. At the largest length scales, our Universe is ruled by gravity, whose gauge structure suggests the existence of a particle-the graviton-that mediates the gravitational force. At the mesoscopic scale, solid-state systems are subjected to gauge fields of different nature: materials can be immersed in external electromagnetic fields, but they can also feature emerging gauge fields in their low-energy description. In this review, we focus on another kind of gauge field: those engineered in systems of ultracold neutral atoms. In these setups, atoms are suitably coupled to laser fields that generate effective gauge potentials in their description. Neutral atoms 'feeling' laser-induced gauge potentials can potentially mimic the behavior of an electron gas subjected to a magnetic field, but also, the interaction of elementary particles with non-Abelian gauge fields. Here, we review different realized and proposed techniques for creating gauge potentials-both Abelian and non-Abelian-in atomic systems and discuss their implication in the context of quantum simulation. While most of these setups concern the realization of background and classical gauge potentials, we conclude with more exotic proposals where these synthetic fields might be made dynamical, in view of simulating interacting gauge theories with cold atoms.
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Affiliation(s)
- N Goldman
- College de France, 11 place Marcelin Berthelot & Laboratoire Kastler Brossel, CNRS, UPMC, ENS, 24 rue Lhomond, 75005 Paris, France
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Bauer J, Salomon C, Demler E. Realizing a Kondo-correlated state with ultracold atoms. PHYSICAL REVIEW LETTERS 2013; 111:215304. [PMID: 24313499 DOI: 10.1103/physrevlett.111.215304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 09/30/2013] [Indexed: 06/02/2023]
Abstract
We propose a novel realization of Kondo physics with ultracold atomic gases. It is based on a Fermi sea of two different hyperfine states of one atom species forming bound states with a different species, which is spatially confined in a trapping potential. We show that different situations displaying Kondo physics can be realized when Feshbach resonances between the species are tuned by a magnetic field and the trapping frequency is varied. We illustrate that a mixture of 40K and 23Na atoms can be used to generate a Kondo-correlated state and that momentum resolved radio frequency spectroscopy can provide unambiguous signatures of the formation of Kondo resonances at the Fermi energy. We discuss how tools of atomic physics can be used to investigate open questions for Kondo physics, such as the extension of the Kondo screening cloud.
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Affiliation(s)
- Johannes Bauer
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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