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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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Aeppli A, Chu A, Bothwell T, Kennedy CJ, Kedar D, He P, Rey AM, Ye J. Hamiltonian engineering of spin-orbit-coupled fermions in a Wannier-Stark optical lattice clock. SCIENCE ADVANCES 2022; 8:eadc9242. [PMID: 36223457 PMCID: PMC9555777 DOI: 10.1126/sciadv.adc9242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 08/25/2022] [Indexed: 06/16/2023]
Abstract
Engineering a Hamiltonian system with tunable interactions provides opportunities to optimize performance for quantum sensing and explore emerging phenomena of many-body systems. An optical lattice clock based on partially delocalized Wannier-Stark states in a gravity-tilted shallow lattice supports superior quantum coherence and adjustable interactions via spin-orbit coupling, thus presenting a powerful spin model realization. The relative strength of the on-site and off-site interactions can be tuned to achieve a zero density shift at a "magic" lattice depth. This mechanism, together with a large number of atoms, enables the demonstration of the most stable atomic clock while minimizing a key systematic uncertainty related to atomic density. Interactions can also be maximized by driving off-site Wannier-Stark transitions, realizing a ferromagnetic to paramagnetic dynamical phase transition.
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Affiliation(s)
- Alexander Aeppli
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Anjun Chu
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO 80309, USA
| | - Tobias Bothwell
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Colin J. Kennedy
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Dhruv Kedar
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Peiru He
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO 80309, USA
| | - Ana Maria Rey
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO 80309, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
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Lu M, Reid GH, Fritsch AR, Piñeiro AM, Spielman IB. Floquet Engineering Topological Dirac Bands. PHYSICAL REVIEW LETTERS 2022; 129:040402. [PMID: 35939027 PMCID: PMC9832990 DOI: 10.1103/physrevlett.129.040402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 05/25/2022] [Accepted: 06/22/2022] [Indexed: 06/15/2023]
Abstract
We experimentally realized a time-periodically modulated 1D lattice for ultracold atoms featuring a pair of linear bands, each with a Floquet winding number. These bands are spin-momentum locked and almost perfectly linear everywhere in the Brillouin zone: a near-ideal realization of the 1D Dirac Hamiltonian. We characterized the Floquet winding number using a form of quantum state tomography, covering the Brillouin zone and following the micromotion through one Floquet period. Last, we altered the modulation timing to lift the topological protection, opening a gap at the Dirac point that grew in proportion to the deviation from the topological configuration.
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Spin transport in a tunable Heisenberg model realized with ultracold atoms. Nature 2020; 588:403-407. [DOI: 10.1038/s41586-020-3033-y] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 09/25/2020] [Indexed: 11/08/2022]
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Dimitrova I, Jepsen N, Buyskikh A, Venegas-Gomez A, Amato-Grill J, Daley A, Ketterle W. Enhanced Superexchange in a Tilted Mott Insulator. PHYSICAL REVIEW LETTERS 2020; 124:043204. [PMID: 32058779 DOI: 10.1103/physrevlett.124.043204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Indexed: 06/10/2023]
Abstract
In an optical lattice, entropy and mass transport by first-order tunneling are much faster than spin transport via superexchange. Here we show that adding a constant force (tilt) suppresses first-order tunneling, but not spin transport, realizing new features for spin Hamiltonians. Suppression of the superfluid transition can stabilize larger systems with faster spin dynamics. For the first time in a many-body spin system, we vary superexchange rates by over a factor of 100 and tune spin-spin interactions via the tilt. In a tilted lattice, defects are immobile and pure spin dynamics can be studied.
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Affiliation(s)
- Ivana Dimitrova
- Department of Physics, Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Niklas Jepsen
- Department of Physics, Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Anton Buyskikh
- Department of Physics and SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - Araceli Venegas-Gomez
- Department of Physics and SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - Jesse Amato-Grill
- Department of Physics, Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Andrew Daley
- Department of Physics and SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom
| | - Wolfgang Ketterle
- Department of Physics, Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Boulier T, Maslek J, Bukov M, Bracamontes C, Magnan E, Lellouch S, Demler E, Goldman N, Porto JV. Parametric heating in a 2D periodically-driven bosonic system: Beyond the weakly-interacting regime. PHYSICAL REVIEW. X 2019; 9:10.1103/physrevx.9.011047. [PMID: 32117577 PMCID: PMC7047775 DOI: 10.1103/physrevx.9.011047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We experimentally investigate the effects of parametric instabilities on the short-time heating process of periodically-driven bosons in 2D optical lattices with a continuous transverse (tube) degree of freedom. We analyze three types of periodic drives: (i) linear along the x-lattice direction only, (ii) linear along the lattice diagonal, and (iii) circular in the lattice plane. In all cases, we demonstrate that the BEC decay is dominated by the emergence of unstable Bogoliubov modes, rather than scattering in higher Floquet bands, in agreement with recent theoretical predictions. The observed BEC depletion rates are much higher when shaking both along x and y directions, as opposed to only x or only y. We also report an explosion of the decay rates at large drive amplitudes, and suggest a phenomenological description beyond Bogoliubov theory. In this strongly-coupled regime, circular drives heat faster than diagonal drives, which illustrates the non-trivial dependence of the heating on the choice of drive.
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Affiliation(s)
- T. Boulier
- Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, College Park, Maryland 20742 USA
- Laboratoire Charles Fabry, Institut dOptique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France
| | - J. Maslek
- Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, College Park, Maryland 20742 USA
| | - M. Bukov
- Department of Physics, University of California Berkeley, CA 94720, USA
| | - C. Bracamontes
- Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, College Park, Maryland 20742 USA
| | - E. Magnan
- Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, College Park, Maryland 20742 USA
- Laboratoire Charles Fabry, Institut dOptique Graduate School, CNRS, Université Paris-Saclay, 91127 Palaiseau cedex, France
| | - S. Lellouch
- Laboratoire de Physique des Lasers, Atomes et Molcules, Université Lille 1 Sciences et Technologies, CNRS; F-59655 Villeneuve d’Ascq Cedex, France
| | - E. Demler
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - N. Goldman
- Center for Nonlinear Phenomena and Complex Systems, Université Libre de Bruxelles, CP 231, Campus Plaine, B-1050 Brussels, Belgium
| | - J. V. Porto
- Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, College Park, Maryland 20742 USA
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Abstract
Quantum simulation, a subdiscipline of quantum computation, can provide valuable insight into difficult quantum problems in physics or chemistry. Ultracold atoms in optical lattices represent an ideal platform for simulations of quantum many-body problems. Within this setting, quantum gas microscopes enable single atom observation and manipulation in large samples. Ultracold atom-based quantum simulators have already been used to probe quantum magnetism, to realize and detect topological quantum matter, and to study quantum systems with controlled long-range interactions. Experiments on many-body systems out of equilibrium have also provided results in regimes unavailable to the most advanced supercomputers. We review recent experimental progress in this field and comment on future directions.
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Affiliation(s)
- Christian Gross
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany.
| | - Immanuel Bloch
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany. .,Germany Fakultät für Physik, Ludwig-Maximilians-Universität, 80799 Munich, Germany
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Abstract
Quantum technologies will ultimately require manipulating many-body quantum systems with high precision. Cold atom experiments represent a stepping stone in that direction: a high degree of control has been achieved on systems of increasing complexity. However, this control is still sub-optimal. In many scenarios, achieving a fast transformation is crucial to fight against decoherence and imperfection effects. Optimal control theory is believed to be the ideal candidate to bridge the gap between early stage proof-of-principle demonstrations and experimental protocols suitable for practical applications. Indeed, it can engineer protocols at the quantum speed limit – the fastest achievable timescale of the transformation. Here, we demonstrate such potential by computing theoretically and verifying experimentally the optimal transformations in two very different interacting systems: the coherent manipulation of motional states of an atomic Bose-Einstein condensate and the crossing of a quantum phase transition in small systems of cold atoms in optical lattices. We also show that such processes are robust with respect to perturbations, including temperature and atom number fluctuations.
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Bohnet JG, Sawyer BC, Britton JW, Wall ML, Rey AM, Foss-Feig M, Bollinger JJ. Quantum spin dynamics and entanglement generation with hundreds of trapped ions. Science 2016; 352:1297-301. [PMID: 27284189 DOI: 10.1126/science.aad9958] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 05/04/2016] [Indexed: 11/03/2022]
Abstract
Quantum simulation of spin models can provide insight into problems that are difficult or impossible to study with classical computers. Trapped ions are an established platform for quantum simulation, but only systems with fewer than 20 ions have demonstrated quantum correlations. We studied quantum spin dynamics arising from an engineered, homogeneous Ising interaction in a two-dimensional array of (9)Be(+) ions in a Penning trap. We verified entanglement in spin-squeezed states of up to 219 ions, directly observing 4.0 ± 0.9 decibels of spectroscopic enhancement, and observed states with non-Gaussian statistics consistent with oversqueezed states. The good agreement with ab initio theory that includes interactions and decoherence lays the groundwork for simulations of the transverse-field Ising model with variable-range interactions, which are generally intractable with classical methods.
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Affiliation(s)
- Justin G Bohnet
- National Institute of Standards and Technology (NIST), Boulder, CO 80305, USA.
| | - Brian C Sawyer
- National Institute of Standards and Technology (NIST), Boulder, CO 80305, USA. Georgia Tech Research Institute, Atlanta, GA 30332, USA
| | - Joseph W Britton
- National Institute of Standards and Technology (NIST), Boulder, CO 80305, USA. Army Research Lab, Adelphi, MD 20783, USA
| | - Michael L Wall
- JILA, NIST, and University of Colorado, Boulder, CO 80309, USA
| | - Ana Maria Rey
- JILA, NIST, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Michael Foss-Feig
- Army Research Lab, Adelphi, MD 20783, USA. Joint Quantum Institute and NIST, Gaithersburg, MD 20899, USA
| | - John J Bollinger
- National Institute of Standards and Technology (NIST), Boulder, CO 80305, USA.
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Beverland ME, Alagic G, Martin MJ, Koller AP, Rey AM, Gorshkov AV. Realizing exactly solvable SU( N) magnets with thermal atoms. PHYSICAL REVIEW. A 2016; 93:10.1103/PhysRevA.93.051601. [PMID: 31276073 PMCID: PMC6604830 DOI: 10.1103/physreva.93.051601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We show that n thermal fermionic alkaline-earth-metal atoms in a flat-bottom trap allow one to robustly implement a spin model displaying two symmetries: the S n symmetry that permutes atoms occupying different vibrational levels of the trap and the SU(N) symmetry associated with N nuclear spin states. The symmetries make the model exactly solvable, which, in turn, enables the analytic study of dynamical processes such as spin diffusion in this SU(N) system. We also show how to use this system to generate entangled states that allow for Heisenberg-limited metrology. This highly symmetric spin model should be experimentally realizable even when the vibrational levels are occupied according to a high-temperature thermal or an arbitrary nonthermal distribution.
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Affiliation(s)
- Michael E Beverland
- Institute for Quantum Information & Matter, California Institute of Technology, Pasadena, California 91125, USA
| | - Gorjan Alagic
- Department of Mathematical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael J Martin
- Institute for Quantum Information & Matter, California Institute of Technology, Pasadena, California 91125, USA
| | - Andrew P Koller
- JILA, NIST, and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Ana M Rey
- JILA, NIST, and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Alexey V Gorshkov
- Joint Quantum Institute and Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
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Greif D, Jotzu G, Messer M, Desbuquois R, Esslinger T. Formation and Dynamics of Antiferromagnetic Correlations in Tunable Optical Lattices. PHYSICAL REVIEW LETTERS 2015; 115:260401. [PMID: 26764974 DOI: 10.1103/physrevlett.115.260401] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Indexed: 06/05/2023]
Abstract
We report on the observation of antiferromagnetic correlations of ultracold fermions in a variety of optical lattice geometries that are well described by the Hubbard model, including dimers, 1D chains, ladders, isolated and coupled honeycomb planes, as well as square and cubic lattices. The dependence of the strength of spin correlations on the specific geometry is experimentally studied by measuring the correlations along different lattice tunneling links, where a redistribution of correlations between the different lattice links is observed. By measuring the correlations in a crossover between distinct geometries, we demonstrate an effective reduction of the dimensionality for our atom numbers and temperatures. We also investigate the formation and redistribution time of spin correlations by dynamically changing the lattice geometry and studying the time evolution of the system. Time scales ranging from a sudden quench of the lattice geometry to an adiabatic evolution are probed.
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Affiliation(s)
- Daniel Greif
- Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Gregor Jotzu
- Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland
| | - Michael Messer
- Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland
| | - Rémi Desbuquois
- Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland
| | - Tilman Esslinger
- Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland
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