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Yan ZZ, Spar BM, Prichard ML, Chi S, Wei HT, Ibarra-García-Padilla E, Hazzard KRA, Bakr WS. Two-Dimensional Programmable Tweezer Arrays of Fermions. PHYSICAL REVIEW LETTERS 2022; 129:123201. [PMID: 36179199 DOI: 10.1103/physrevlett.129.123201] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 06/27/2022] [Accepted: 07/29/2022] [Indexed: 06/16/2023]
Abstract
We prepare high-filling two-component arrays of tens of fermionic ^{6}Li atoms in optical tweezers, with the atoms in the ground motional state of each tweezer. Using a stroboscopic technique, we configure the arrays in various two-dimensional geometries with negligible Floquet heating. A full spin- and density-resolved readout of individual sites allows us to postselect near-zero entropy initial states for fermionic quantum simulation. We prepare a correlated state in a two-by-two tunnel-coupled Hubbard plaquette, demonstrating all the building blocks for realizing a programmable fermionic quantum simulator.
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Affiliation(s)
- Zoe Z Yan
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Benjamin M Spar
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Max L Prichard
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Sungjae Chi
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Hao-Tian Wei
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
- Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Eduardo Ibarra-García-Padilla
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
- Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Kaden R A Hazzard
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
- Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Waseem S Bakr
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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2
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Sobirey L, Biss H, Luick N, Bohlen M, Moritz H, Lompe T. Observing the Influence of Reduced Dimensionality on Fermionic Superfluids. PHYSICAL REVIEW LETTERS 2022; 129:083601. [PMID: 36053698 DOI: 10.1103/physrevlett.129.083601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 06/28/2022] [Indexed: 06/15/2023]
Abstract
Understanding the origins of unconventional superconductivity has been a major focus of condensed matter physics for many decades. While many questions remain unanswered, experiments have found the highest critical temperatures in layered two-dimensional materials. However, to what extent the remarkable stability of these strongly correlated 2D superfluids is affected by their reduced dimensionality is still an open question. Here, we use dilute gases of ultracold fermionic atoms as a model system to directly observe the influence of dimensionality on the stability of strongly interacting fermionic superfluids. We find that the superfluid gap follows the same universal function of the interaction strength regardless of dimensionality, which suggests that there is no inherent difference in the stability of two- and three-dimensional fermionic superfluids. Finally, we compare our data to results from solid state systems and find a similar relation between the interaction strength and the gap for a wide range of two- and three-dimensional superconductors.
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Affiliation(s)
- Lennart Sobirey
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Hauke Biss
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg
| | - Niclas Luick
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg
| | - Markus Bohlen
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg
| | - Henning Moritz
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg
| | - Thomas Lompe
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg
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3
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He YY, Shi H, Zhang S. Precision Many-Body Study of the Berezinskii-Kosterlitz-Thouless Transition and Temperature-Dependent Properties in the Two-Dimensional Fermi Gas. PHYSICAL REVIEW LETTERS 2022; 129:076403. [PMID: 36018705 DOI: 10.1103/physrevlett.129.076403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 07/13/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
We perform large-scale, numerically exact calculations on the two-dimensional interacting Fermi gas with a contact attraction. Reaching much larger lattice sizes and lower temperatures than previously possible, we determine systematically the finite-temperature phase diagram of the Berezinskii-Kosterlitz-Thouless (BKT) transitions for interaction strengths ranging from BCS to crossover to BEC regimes. The evolutions of the pairing wave functions and the fermion and Cooper pair momentum distributions with temperature are accurately characterized. In the crossover regime, we find that the contact has a nonmonotonic temperature dependence, first increasing as temperature is lowered, and then showing a slight decline below the BKT transition temperature to approach the ground-state value from above.
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Affiliation(s)
- Yuan-Yao He
- Institute of Modern Physics, Northwest University, Xi'an 710127, China
- Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi'an 710127, China
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, USA
| | - Hao Shi
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA
| | - Shiwei Zhang
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, USA
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4
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Sobirey L, Luick N, Bohlen M, Biss H, Moritz H, Lompe T. Observation of superfluidity in a strongly correlated two-dimensional Fermi gas. Science 2021; 372:844-846. [PMID: 34016777 DOI: 10.1126/science.abc8793] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 04/17/2021] [Indexed: 11/02/2022]
Abstract
Understanding how strongly correlated two-dimensional (2D) systems can give rise to unconventional superconductivity with high critical temperatures is one of the major unsolved problems in condensed matter physics. Ultracold 2D Fermi gases have emerged as clean and controllable model systems to study the interplay of strong correlations and reduced dimensionality, but direct evidence of superfluidity in these systems has been missing. We demonstrate superfluidity in an ultracold 2D Fermi gas by moving a periodic potential through the system and observing no dissipation below a critical velocity v c We measure v c as a function of interaction strength and find a maximum in the crossover regime between bosonic and fermionic superfluidity. Our measurements enable systematic studies of the influence of reduced dimensionality on fermionic superfluidity.
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Affiliation(s)
- Lennart Sobirey
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany. .,The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Niclas Luick
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Markus Bohlen
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.,Laboratoire Kastler Brossel, ENS-PSL Research University, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Hauke Biss
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Henning Moritz
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Thomas Lompe
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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5
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Luick N, Sobirey L, Bohlen M, Singh VP, Mathey L, Lompe T, Moritz H. An ideal Josephson junction in an ultracold two-dimensional Fermi gas. Science 2020; 369:89-91. [DOI: 10.1126/science.aaz2342] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 05/07/2020] [Indexed: 11/02/2022]
Affiliation(s)
- Niclas Luick
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Lennart Sobirey
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Markus Bohlen
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Vijay Pal Singh
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Ludwig Mathey
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Thomas Lompe
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Henning Moritz
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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6
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Zdybel P, Jakubczyk P. Effective potential and quantum criticality for imbalanced Fermi mixtures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:305604. [PMID: 29893718 DOI: 10.1088/1361-648x/aacc00] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We study the analytical structure of the effective action for spin- and mass-imbalanced Fermi mixtures at the onset of the superfluid state. Of our particular focus is the possibility of suppressing the tricritical temperature to zero, so that the transition remains continuous down to T = 0 and the phase diagram hosts a quantum critical point. At mean-field level we analytically identify such a possibility in a regime of parameters in dimensionality d = 3. In contrast, in d = 2 we demonstrate that the occurrence of a quantum critical point is (at the mean-field level) excluded. We show that the Landau expansion of the effective potential remains well-defined in the limit [Formula: see text] except for a subset of model parameters which includes the standard BCS limit. We calculate the mean-field asymptotic shape of the transition line. Employing the functional renormalization group framework we go beyond the mean field theory and demonstrate the stability of the quantum critical point in d = 3 with respect to fluctuations.
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Affiliation(s)
- Piotr Zdybel
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
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7
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Hueck K, Luick N, Sobirey L, Siegl J, Lompe T, Moritz H. Two-Dimensional Homogeneous Fermi Gases. PHYSICAL REVIEW LETTERS 2018; 120:060402. [PMID: 29481215 DOI: 10.1103/physrevlett.120.060402] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 11/07/2017] [Indexed: 06/08/2023]
Abstract
We report on the experimental realization of homogeneous two-dimensional (2D) Fermi gases trapped in a box potential. In contrast to harmonically trapped gases, these homogeneous 2D systems are ideally suited to probe local as well as nonlocal properties of strongly interacting many-body systems. As a first benchmark experiment, we use a local probe to measure the density of a noninteracting 2D Fermi gas as a function of the chemical potential and find excellent agreement with the corresponding equation of state. We then perform matter wave focusing to extract the momentum distribution of the system and directly observe Pauli blocking in a near unity occupation of momentum states. Finally, we measure the momentum distribution of an interacting homogeneous 2D gas in the crossover between attractively interacting fermions and bosonic dimers.
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Affiliation(s)
- Klaus Hueck
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Niclas Luick
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Lennart Sobirey
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Jonas Siegl
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Thomas Lompe
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Henning Moritz
- Institut für Laserphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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8
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Murthy PA, Neidig M, Klemt R, Bayha L, Boettcher I, Enss T, Holten M, Zürn G, Preiss PM, Jochim S. High-temperature pairing in a strongly interacting two-dimensional Fermi gas. Science 2018; 359:452-455. [DOI: 10.1126/science.aan5950] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 12/06/2017] [Indexed: 11/02/2022]
Affiliation(s)
| | - Mathias Neidig
- Physics Institute, Heidelberg University, Heidelberg, Germany
| | - Ralf Klemt
- Physics Institute, Heidelberg University, Heidelberg, Germany
| | - Luca Bayha
- Physics Institute, Heidelberg University, Heidelberg, Germany
| | - Igor Boettcher
- Department of Physics, Simon Fraser University, Burnaby, BC, Canada
| | - Tilman Enss
- Institute for Theoretical Physics, Heidelberg University, Heidelberg, Germany
| | - Marvin Holten
- Physics Institute, Heidelberg University, Heidelberg, Germany
| | - Gerhard Zürn
- Physics Institute, Heidelberg University, Heidelberg, Germany
| | | | - Selim Jochim
- Physics Institute, Heidelberg University, Heidelberg, Germany
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9
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Brown PT, Mitra D, Guardado-Sanchez E, Schauß P, Kondov SS, Khatami E, Paiva T, Trivedi N, Huse DA, Bakr WS. Spin-imbalance in a 2D Fermi-Hubbard system. Science 2017; 357:1385-1388. [DOI: 10.1126/science.aam7838] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 08/24/2017] [Indexed: 11/02/2022]
Abstract
The interplay of strong interactions and magnetic fields gives rise to unusual forms of superconductivity and magnetism in quantum many-body systems. Here, we present an experimental study of the two-dimensional Fermi-Hubbard model—a paradigm for strongly correlated fermions on a lattice—in the presence of a Zeeman field and varying doping. Using site-resolved measurements, we revealed anisotropic antiferromagnetic correlations, a precursor to long-range canted order. We observed nonmonotonic behavior of the local polarization with doping for strong interactions, which we attribute to the evolution from an antiferromagnetic insulator to a metallic phase. Our results pave the way to experimentally mapping the low-temperature phase diagram of the Fermi-Hubbard model as a function of both doping and spin polarization, for which many open questions remain.
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