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Bhowmik A, Alon OE. Coupled-cluster theory for trapped bosonic mixtures. J Chem Phys 2024; 160:044105. [PMID: 38258928 DOI: 10.1063/5.0176145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 12/26/2023] [Indexed: 01/24/2024] Open
Abstract
We develop a coupled-cluster theory for bosonic mixtures of binary species in external traps, providing a promising theoretical approach to demonstrate highly accurately the many-body physics of mixtures of Bose-Einstein condensates. The coupled-cluster wavefunction for the binary species is obtained when an exponential cluster operator eT, where T = T(1) + T(2) + T(12) and T(1) accounts for excitations in species-1, T(2) for excitations in species-2, and T(12) for combined excitations in both species, acts on the ground state configuration prepared by accumulating all bosons in a single orbital for each species. We have explicitly derived the working equations for bosonic mixtures by truncating the cluster operator up to the single and double excitations and using arbitrary sets of orthonormal orbitals for each of the species. Furthermore, the comparatively simplified version of the working equations are formulated using the Fock-like operators. Finally, using an exactly solvable many-body model for bosonic mixtures that exists in the literature allows us to implement and test the performance and accuracy of the coupled-cluster theory for situations with balanced as well as imbalanced boson numbers and for weak to moderately strong intra- and interspecies interaction strengths. The comparison between our computed results using coupled-cluster theory with the respective analytical exact results displays remarkable agreement exhibiting excellent success of the coupled-cluster theory for bosonic mixtures. All in all, the correlation exhaustive coupled-cluster theory shows encouraging results and could be a promising approach in paving the way for high-accuracy modeling of various bosonic mixture systems.
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Affiliation(s)
- Anal Bhowmik
- Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, Norman, Oklahoma 73019, USA
- Center for Quantum Research and Technology, The University of Oklahoma, Norman, Oklahoma 73019, USA
- Department of Physics, University of Haifa, Haifa 3498838, Israel
- Haifa Research Center for Theoretical Physics and Astrophysics, University of Haifa, Haifa 3498838, Israel
| | - Ofir E Alon
- Department of Physics, University of Haifa, Haifa 3498838, Israel
- Haifa Research Center for Theoretical Physics and Astrophysics, University of Haifa, Haifa 3498838, Israel
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2
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Chomaz L, Ferrier-Barbut I, Ferlaino F, Laburthe-Tolra B, Lev BL, Pfau T. Dipolar physics: a review of experiments with magnetic quantum gases. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 86:026401. [PMID: 36583342 DOI: 10.1088/1361-6633/aca814] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 12/02/2022] [Indexed: 06/17/2023]
Abstract
Since the achievement of quantum degeneracy in gases of chromium atoms in 2004, the experimental investigation of ultracold gases made of highly magnetic atoms has blossomed. The field has yielded the observation of many unprecedented phenomena, in particular those in which long-range and anisotropic dipole-dipole interactions (DDIs) play a crucial role. In this review, we aim to present the aspects of the magnetic quantum-gas platform that make it unique for exploring ultracold and quantum physics as well as to give a thorough overview of experimental achievements. Highly magnetic atoms distinguish themselves by the fact that their electronic ground-state configuration possesses a large electronic total angular momentum. This results in a large magnetic moment and a rich electronic transition spectrum. Such transitions are useful for cooling, trapping, and manipulating these atoms. The complex atomic structure and large dipolar moments of these atoms also lead to a dense spectrum of resonances in their two-body scattering behaviour. These resonances can be used to control the interatomic interactions and, in particular, the relative importance of contact over dipolar interactions. These features provide exquisite control knobs for exploring the few- and many-body physics of dipolar quantum gases. The study of dipolar effects in magnetic quantum gases has covered various few-body phenomena that are based on elastic and inelastic anisotropic scattering. Various many-body effects have also been demonstrated. These affect both the shape, stability, dynamics, and excitations of fully polarised repulsive Bose or Fermi gases. Beyond the mean-field instability, strong dipolar interactions competing with slightly weaker contact interactions between magnetic bosons yield new quantum-stabilised states, among which are self-bound droplets, droplet assemblies, and supersolids. Dipolar interactions also deeply affect the physics of atomic gases with an internal degree of freedom as these interactions intrinsically couple spin and atomic motion. Finally, long-range dipolar interactions can stabilise strongly correlated excited states of 1D gases and also impact the physics of lattice-confined systems, both at the spin-polarised level (Hubbard models with off-site interactions) and at the spinful level (XYZ models). In the present manuscript, we aim to provide an extensive overview of the various related experimental achievements up to the present.
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Affiliation(s)
- Lauriane Chomaz
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
- Physikalisches Institut der Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
| | - Igor Ferrier-Barbut
- Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany
- Université Paris-Saclay, Institut d'Optique Graduate School, CNRS, Laboratoire Charles Fabry, 91127 Palaiseau, France
| | - Francesca Ferlaino
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria
| | - Bruno Laburthe-Tolra
- Université Sorbonne Paris Nord, Laboratoire de Physique des Lasers, F-93430 Villetaneuse, France
- CNRS, UMR 7538, LPL, F-93430 Villetaneuse, France
| | - Benjamin L Lev
- Departments of Physics and Applied Physics and Ginzton Laboratory, Stanford University, Stanford, CA 94305, United States of America
| | - Tilman Pfau
- Physikalisches Institut and Center for Integrated Quantum Science and Technology, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany
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Norcia MA, Poli E, Politi C, Klaus L, Bland T, Mark MJ, Santos L, Bisset RN, Ferlaino F. Can Angular Oscillations Probe Superfluidity in Dipolar Supersolids? PHYSICAL REVIEW LETTERS 2022; 129:040403. [PMID: 35939003 DOI: 10.1103/physrevlett.129.040403] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/03/2022] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
Angular oscillations can provide a useful probe of the superfluid properties of a system. Such measurements have recently been applied to dipolar supersolids, which exhibit both density modulation and phase coherence, and for which robust probes of superfluidity are particularly interesting. So far, these investigations have been confined to linear droplet arrays, which feature relatively simple excitation spectra, but limited sensitivity to the effects of superfluidity. Here, we explore angular oscillations in systems with 2D structure which, in principle, have greater sensitivity to superfluidity. In both experiment and simulation, we find that the interplay of superfluid and crystalline excitations leads to a frequency of angular oscillations that remains nearly unchanged even when the superfluidity of the system is altered dramatically. This indicates that angular oscillation measurements do not always provide a robust experimental probe of superfluidity with typical experimental protocols.
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Affiliation(s)
- Matthew A Norcia
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Innsbruck 6020, Austria
| | - Elena Poli
- Institut für Experimentalphysik, Universität Innsbruck, Innsbruck 6020, Austria
| | - Claudia Politi
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Innsbruck 6020, Austria
- Institut für Experimentalphysik, Universität Innsbruck, Innsbruck 6020, Austria
| | - Lauritz Klaus
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Innsbruck 6020, Austria
- Institut für Experimentalphysik, Universität Innsbruck, Innsbruck 6020, Austria
| | - Thomas Bland
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Innsbruck 6020, Austria
- Institut für Experimentalphysik, Universität Innsbruck, Innsbruck 6020, Austria
| | - Manfred J Mark
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Innsbruck 6020, Austria
- Institut für Experimentalphysik, Universität Innsbruck, Innsbruck 6020, Austria
| | - Luis Santos
- Institut für Theoretische Physik, Leibniz Universität Hannover, 30167 Hannover, Germany
| | - Russell N Bisset
- Institut für Experimentalphysik, Universität Innsbruck, Innsbruck 6020, Austria
| | - Francesca Ferlaino
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Innsbruck 6020, Austria
- Institut für Experimentalphysik, Universität Innsbruck, Innsbruck 6020, Austria
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4
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Mixtures of Dipolar Gases in Two Dimensions: A Quantum Monte Carlo Study. CONDENSED MATTER 2022. [DOI: 10.3390/condmat7020032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
We studied the miscibility of two dipolar quantum gases in the limit of zero temperature. The system under study is composed of a mixture of two Bose gases with dominant dipolar interaction in a two-dimensional harmonic confinement. The dipolar moments are all considered to be perpendicular to the plane, turning the dipolar potential in a purely repulsive and isotropic model. Our analysis is carried out by using the diffusion Monte Carlo method, which allows for an exact solution to the many-body problem within some statistical noise. Our results show that the miscibility between the two species is rather constrained as a function of the relative dipolar moments and masses of the two components. A narrow regime is predicted where both species mix and we introduce an adimensional parameter whose value quite accurately predicts the miscibility of the two dipolar gases.
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Guijarro G, Astrakharchik GE, Boronat J. Ultradilute Quantum Liquid of Dipolar Atoms in a Bilayer. PHYSICAL REVIEW LETTERS 2022; 128:063401. [PMID: 35213182 DOI: 10.1103/physrevlett.128.063401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 10/07/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
We show that ultradilute quantum liquids can be formed with ultracold bosonic dipolar atoms in a bilayer geometry. Contrary to previous realizations of ultradilute liquids, there is no need for stabilizing the system with an additional repulsive short-range potential. The advantage of the proposed system is that dipolar interactions on their own are sufficient for creation of a self-bound state and no additional short-range potential is needed for the stabilization. We perform quantum Monte Carlo simulations and find a rich ground-state phase diagram that contains quantum phase transitions between liquid, solid, atomic gas, and molecular gas phases. The stabilization mechanism of the liquid phase is consistent with the microscopic scenario in which the effective dimer-dimer attraction is balanced by an effective three-dimer repulsion. The equilibrium density of the liquid, which is extremely small, can be controlled by the interlayer distance. From the equation of state, we extract the spinodal density, below which the homogeneous system breaks into droplets. Our results offer a new example of a two-dimensional interacting dipolar liquid in a clean and highly controllable setup.
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Affiliation(s)
- G Guijarro
- Departament de Física, Campus Nord B4-B5, Universitat Politécnica de Catalunya, E-08034 Barcelona, Spain
| | - G E Astrakharchik
- Departament de Física, Campus Nord B4-B5, Universitat Politécnica de Catalunya, E-08034 Barcelona, Spain
| | - J Boronat
- Departament de Física, Campus Nord B4-B5, Universitat Politécnica de Catalunya, E-08034 Barcelona, Spain
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Guijarro G, Astrakharchik GE, Boronat J. Quantum halo states in two-dimensional dipolar clusters. Sci Rep 2021; 11:19437. [PMID: 34593895 PMCID: PMC8484373 DOI: 10.1038/s41598-021-98838-4] [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: 05/16/2021] [Accepted: 09/14/2021] [Indexed: 11/11/2022] Open
Abstract
A halo is an intrinsically quantum object defined as a bound state of a spatial size which extends deeply into the classically forbidden region. Previously, halos have been observed in bound states of two and less frequently of three atoms. Here, we propose a realization of halo states containing as many as six atoms. We report the binding energies, pair correlation functions, spatial distributions, and sizes of few-body clusters composed by bosonic dipolar atoms in a bilayer geometry. We find two very distinct halo structures, for large interlayer separation the halo structure is roughly symmetric and we discover an unusual highly anisotropic shape of halo states close to the unbinding threshold. Our results open avenues of using ultracold gases for the experimental realization of halos composed by atoms with dipolar interactions and containing as many as six atoms.
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Affiliation(s)
- G Guijarro
- Departament de Física, Campus Nord B4-B5, Universitat Politècnica de Catalunya, 08034, Barcelona, Spain.
| | - G E Astrakharchik
- Departament de Física, Campus Nord B4-B5, Universitat Politècnica de Catalunya, 08034, Barcelona, Spain
| | - J Boronat
- Departament de Física, Campus Nord B4-B5, Universitat Politècnica de Catalunya, 08034, Barcelona, Spain
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7
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Two-dimensional supersolidity in a dipolar quantum gas. Nature 2021; 596:357-361. [PMID: 34408330 DOI: 10.1038/s41586-021-03725-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 06/14/2021] [Indexed: 02/07/2023]
Abstract
Supersolid states simultaneously feature properties typically associated with a solid and with a superfluid. Like a solid, they possess crystalline order, manifesting as a periodic modulation of the particle density; but unlike a typical solid, they also have superfluid properties, resulting from coherent particle delocalization across the system. Such states were initially envisioned in the context of bulk solid helium, as a possible answer to the question of whether a solid could have superfluid properties1-5. Although supersolidity has not been observed in solid helium (despite much effort)6, ultracold atomic gases provide an alternative approach, recently enabling the observation and study of supersolids with dipolar atoms7-16. However, unlike the proposed phenomena in helium, these gaseous systems have so far only shown supersolidity along a single direction. Here we demonstrate the extension of supersolid properties into two dimensions by preparing a supersolid quantum gas of dysprosium atoms on both sides of a structural phase transition similar to those occurring in ionic chains17-20, quantum wires21,22 and theoretically in chains of individual dipolar particles23,24. This opens the possibility of studying rich excitation properties25-28, including vortex formation29-31, and ground-state phases with varied geometrical structure7,32 in a highly flexible and controllable system.
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8
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Schuster T, Flicker F, Li M, Kotochigova S, Moore JE, Ye J, Yao NY. Realizing Hopf Insulators in Dipolar Spin Systems. PHYSICAL REVIEW LETTERS 2021; 127:015301. [PMID: 34270282 DOI: 10.1103/physrevlett.127.015301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 09/24/2020] [Accepted: 04/19/2021] [Indexed: 06/13/2023]
Abstract
The Hopf insulator is a weak topological insulator characterized by an insulating bulk with conducting edge states protected by an integer-valued linking number invariant. The state exists in three-dimensional two-band models. We demonstrate that the Hopf insulator can be naturally realized in lattices of dipolar-interacting spins, where spin exchange plays the role of particle hopping. The long-ranged, anisotropic nature of the dipole-dipole interactions allows for the precise detail required in the momentum-space structure, while different spin orientations ensure the necessary structure of the complex phases of the hoppings. Our model features robust gapless edge states at both smooth edges, as well as sharp edges obeying a certain crystalline symmetry, despite the breakdown of the two-band picture at the latter. In an accompanying paper [T. Schuster et al., Phys. Rev. A 103, AW11986 (2021)PLRAAN2469-9926] we provide a specific experimental blueprint for implementing our proposal using ultracold polar molecules of ^{40}K^{87}Rb.
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Affiliation(s)
- Thomas Schuster
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Felix Flicker
- Department of Physics, University of California, Berkeley, California 94720, USA
- Rudolph Peierls Centre for Theoretical Physics, University of Oxford, Department of Physics, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Ming Li
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
| | | | - Joel E Moore
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Norman Y Yao
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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9
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Bisset RN, Ardila LAP, Santos L. Quantum Droplets of Dipolar Mixtures. PHYSICAL REVIEW LETTERS 2021; 126:025301. [PMID: 33512237 DOI: 10.1103/physrevlett.126.025301] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 11/03/2020] [Indexed: 05/12/2023]
Abstract
Recently achieved two-component dipolar Bose-Einstein condensates open exciting possibilities for the study of mixtures of ultradilute quantum liquids. While nondipolar self-bound (without external confinement) mixtures are necessarily miscible with an approximately fixed ratio between the two densities, the density ratio for the dipolar case is free. Therefore, self-bound dipolar mixtures present qualitatively novel and much richer physics, characterized by three possible ground-state phases: miscible, symmetric immiscible, and asymmetric immiscible, which may in principle occur at any population imbalance. Self-bound immiscible droplets are possible due to mutual nonlocal intercomponent attraction, which results in the formation of a droplet molecule. Moreover, our analysis of the impurity regime shows that quantum fluctuations in the majority component crucially modify the miscibility of impurities. Our work opens intriguing perspectives for the exploration of spinor physics in ultradilute liquids, which should resemble to some extent that of ^{4}He-^{3}He droplets and impurity-doped helium droplets.
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Affiliation(s)
- R N Bisset
- Institut für Theoretische Physik, Leibniz Universität Hannover, Germany
- Institut für Experimentalphysik, Universität Innsbruck, Innsbruck, Austria
| | - L A Peña Ardila
- Institut für Theoretische Physik, Leibniz Universität Hannover, Germany
| | - L Santos
- Institut für Theoretische Physik, Leibniz Universität Hannover, Germany
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10
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Smith JC, Baillie D, Blakie PB. Quantum Droplet States of a Binary Magnetic Gas. PHYSICAL REVIEW LETTERS 2021; 126:025302. [PMID: 33512210 DOI: 10.1103/physrevlett.126.025302] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 11/03/2020] [Indexed: 06/12/2023]
Abstract
Quantum droplets can emerge in bosonic binary magnetic gases (BMGs) from the interplay of short- and long-ranged interactions, and quantum fluctuations. We develop an extended mean field theory for this system and use it to predict equilibrium and dynamical properties of BMG droplets. We present a phase diagram and characterize miscible and immiscible droplet states. We also show that a single-component self-bound droplet can bind another magnetic component, which is not in the droplet regime, due to the interspecies dipole-dipole interactions. Our results should be realizable in experiments with mixtures of highly magnetic lanthanide atoms.
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Affiliation(s)
- Joseph C Smith
- Dodd-Walls Centre for Photonic and Quantum Technologies, New Zealand and Department of Physics, University of Otago, Dunedin 9016, New Zealand
| | - D Baillie
- Dodd-Walls Centre for Photonic and Quantum Technologies, New Zealand and Department of Physics, University of Otago, Dunedin 9016, New Zealand
| | - P B Blakie
- Dodd-Walls Centre for Photonic and Quantum Technologies, New Zealand and Department of Physics, University of Otago, Dunedin 9016, New Zealand
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Plotkin-Swing B, Wirth A, Gochnauer D, Rahman T, McAlpine KE, Gupta S. Crossed-beam slowing to enhance narrow-line ytterbium magneto-optic traps. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:093201. [PMID: 33003806 DOI: 10.1063/5.0011361] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 08/15/2020] [Indexed: 06/11/2023]
Abstract
We demonstrate a method to enhance the atom loading rate of a ytterbium (Yb) magneto-optic trap (MOT) operating on the 556 nm 1S0 → 3P1 intercombination transition (narrow linewidth Γg = 2π × 182 kHz). Following traditional Zeeman slowing of an atomic beam near the 399 nm 1S0 → 1P1 transition (broad linewidth Γp = 2π × 29 MHz), two laser beams in a crossed-beam geometry, frequency tuned near the same transition, provide additional slowing immediately prior to the MOT. Using this technique, we observe an improvement by a factor of 6 in the atom loading rate of a narrow-line Yb MOT. The relative simplicity and generality of this approach make it readily adoptable to other experiments involving narrow-line MOTs. We also present a numerical simulation of this two-stage slowing process, which shows good agreement with the observed dependence on experimental parameters, and use it to assess potential improvements to the method.
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Affiliation(s)
| | - Anna Wirth
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - Daniel Gochnauer
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - Tahiyat Rahman
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | | | - Subhadeep Gupta
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
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12
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Ravensbergen C, Soave E, Corre V, Kreyer M, Huang B, Kirilov E, Grimm R. Resonantly Interacting Fermi-Fermi Mixture of ^{161}Dy and ^{40}K. PHYSICAL REVIEW LETTERS 2020; 124:203402. [PMID: 32501049 DOI: 10.1103/physrevlett.124.203402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 03/12/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
We report on the realization of a Fermi-Fermi mixture of ultracold atoms that combines mass imbalance, tunability, and collisional stability. In an optically trapped sample of ^{161}Dy and ^{40}K, we identify a broad Feshbach resonance centered at a magnetic field of 217 G. Hydrodynamic expansion profiles in the resonant interaction regime reveal a bimodal behavior resulting from mass imbalance. Lifetime studies on resonance show a suppression of inelastic few-body processes by orders of magnitude, which we interpret as a consequence of the fermionic nature of our system. The resonant mixture opens up intriguing perspectives for studies on novel states of strongly correlated fermions with mass imbalance.
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Affiliation(s)
- C Ravensbergen
- Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation (IQOQI), Österreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria
| | - E Soave
- Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria
| | - V Corre
- Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation (IQOQI), Österreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria
| | - M Kreyer
- Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria
| | - B Huang
- Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation (IQOQI), Österreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria
| | - E Kirilov
- Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria
| | - R Grimm
- Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation (IQOQI), Österreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria
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13
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Sowiński T, Ángel García-March M. One-dimensional mixtures of several ultracold atoms: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:104401. [PMID: 31404916 DOI: 10.1088/1361-6633/ab3a80] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Recent theoretical and experimental progress on studying one-dimensional systems of bosonic, fermionic, and Bose-Fermi mixtures of a few ultracold atoms confined in traps is reviewed in the broad context of mesoscopic quantum physics. We pay special attention to limiting cases of very strong or very weak interactions and transitions between them. For bosonic mixtures, we describe the developments in systems of three and four atoms as well as different extensions to larger numbers of particles. We also briefly review progress in the case of spinor Bose gases of a few atoms. For fermionic mixtures, we discuss a special role of spin and present a detailed discussion of the two- and three-atom cases. We discuss the advantages and disadvantages of different computation methods applied to systems with intermediate interactions. In the case of very strong repulsion, close to the infinite limit, we discuss approaches based on effective spin chain descriptions. We also report on recent studies on higher-spin mixtures and inter-component attractive forces. For both statistics, we pay particular attention to impurity problems and mass imbalance cases. Finally, we describe the recent advances on trapped Bose-Fermi mixtures, which allow for a theoretical combination of previous concepts, well illustrating the importance of quantum statistics and inter-particle interactions. Lastly, we report on fundamental questions related to the subject which we believe will inspire further theoretical developments and experimental verification.
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Affiliation(s)
- Tomasz Sowiński
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
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14
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Dynamical formation of a strongly correlated dark condensate of dipolar excitons. Proc Natl Acad Sci U S A 2019; 116:18328-18333. [PMID: 31451654 DOI: 10.1073/pnas.1903374116] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Strongly interacting bosons display a rich variety of quantum phases, the study of which has so far been focused in the dilute regime, at a fixed number of particles. Here we demonstrate the formation of a dense Bose-Einstein condensate in a long-lived dark spin state of 2D dipolar excitons. A dark condensate of weakly interacting excitons is very fragile, being unstable against a coherent coupling of dark and bright spin states. Remarkably, we find that strong dipole-dipole interactions stabilize the dark condensate. As a result, the dark phase persists up to densities high enough for a dark quantum liquid to form. The striking experimental observation of a step-like dependence of the exciton density on the pump power is reproduced quantitatively by a model describing the nonequilibrium dynamics of driven coupled dark and bright condensates. This unique behavior marks a dynamical condensation to dark states with lifetimes as long as a millisecond, followed by a brightening transition at high densities.
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