1
|
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.
Collapse
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
| |
Collapse
|
2
|
Zhang YC. Superfluid density, Josephson relation and pairing fluctuations in a multi-component fermion superfluid. Sci Rep 2021; 11:21847. [PMID: 34750432 PMCID: PMC8575947 DOI: 10.1038/s41598-021-01261-y] [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: 10/01/2021] [Accepted: 10/26/2021] [Indexed: 11/11/2022] Open
Abstract
In this work, a Josephson relation is generalized to a multi-component fermion superfluid. Superfluid density is expressed through a two-particle Green function for pairing states. When the system has only one gapless collective excitation mode, the Josephson relation is simplified, which is given in terms of the superfluid order parameters and the trace of two-particle normal Green function. In addition, it is found that the matrix elements of two-particle Green function is directly related to the matrix elements of the pairing fluctuations of superfluid order parameters. Furthermore, in the presence of inversion symmetry, the superfluid density is given in terms of the pairing fluctuation matrix. The results of the superfluid density in Haldane model show that the generalized Josephson relation can be also applied to a multi-band fermion superfluid in lattice.
Collapse
Affiliation(s)
- Yi-Cai Zhang
- School of Physics and Materials Science, Guangzhou University, Guangzhou, 510006, People's Republic of China.
| |
Collapse
|
3
|
Wu YR, Zhang XF, Liu CF, Liu WM, Zhang YC. Superfluid density and collective modes of fermion superfluid in dice lattice. Sci Rep 2021; 11:13572. [PMID: 34193952 PMCID: PMC8245560 DOI: 10.1038/s41598-021-93007-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/18/2021] [Indexed: 11/30/2022] Open
Abstract
The superfluid properties of attractive Hubbard model in dice lattice are investigated. It is found that three superfluid order parameters increase as the interaction increases. When the filling factor falls into the flat band, due to the infinite large density of states, the resultant superfluid order parameters are proportional to interaction strength, which is in striking contrast with the exponentially small counterparts in usual superfluid (or superconductor). When the interaction is weak, and the filling factor is near the bottom of the lowest band (or the top of highest band), the superfluid density is determined by the effective mass of the lowest (or highest) single-particle band. When the interaction is strong and filling factor is small, the superfluid density is inversely proportional to interaction strength, which is related to effective mass of tightly bound pairs. In the strong interaction limit and finite filling, the asymptotic behaviors of superfluid density can be captured by a parabolic function of filling factor. Furthermore, when the filling is in flat band, the superfluid density shows a logarithmic singularity as the interaction approaches zero. In addition, there exist three undamped collective modes for strong interactions. The lowest excitation is gapless phonon, which is characterized by the total density oscillations. The two others are gapped Leggett modes, which correspond relative density fluctuations between sublattices. The collective modes are also reflected in the two-particle spectral functions by sharp peaks. Furthermore, it is found that the two-particle spectral functions satisfy an exact sum-rule, which is directly related to the filling factor (or density of particle). The sum-rule of the spectral functions may be useful to distinguish between the hole-doped and particle-doped superfluid (superconductor) in experiments.
Collapse
Affiliation(s)
- Yu-Rong Wu
- School of Physics and Materials Science, Guangzhou University, Guangzhou, 510006, China
| | - Xiao-Fei Zhang
- Key Laboratory of Time and Frequency Primary Standards, National Time Service Center, Chinese Academy of Sciences, Xi'an, 710600, China.,School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chao-Fei Liu
- School of Science, Jiangxi University of Science and Technology, Ganzhou, 341000, China
| | - Wu-Ming Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Yi-Cai Zhang
- School of Physics and Materials Science, Guangzhou University, Guangzhou, 510006, China.
| |
Collapse
|
4
|
Yoshida H, Katsura H. Rigorous Results on the Ground State of the Attractive SU(N) Hubbard Model. PHYSICAL REVIEW LETTERS 2021; 126:100201. [PMID: 33784130 DOI: 10.1103/physrevlett.126.100201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/28/2021] [Indexed: 06/12/2023]
Abstract
We study the attractive SU(N) Hubbard model with particle-hole symmetry. The model is defined on a bipartite lattice with the number of sites N_{A} (N_{B}) in the A (B) sublattice. We prove three theorems that allow us to identify the basic ground-state properties: the degeneracy, the fermion number, and the SU(N) quantum number. We also show that the ground state exhibits charge density wave order when |N_{A}-N_{B}| is macroscopically large. The theorems hold for a bipartite lattice in any dimension, even without translation invariance.
Collapse
Affiliation(s)
- Hironobu Yoshida
- Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
| | - Hosho Katsura
- Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
- Institute for Physics of Intelligence, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
- Trans-scale Quantum Science Institute, The University of Tokyo, 7-3-1, Hongo, Tokyo 113-0033, Japan
| |
Collapse
|
5
|
Briggeman M, Tomczyk M, Tian B, Lee H, Lee JW, He Y, Tylan-Tyler A, Huang M, Eom CB, Pekker D, Mong RSK, Irvin P, Levy J. Pascal conductance series in ballistic one-dimensional LaAlO 3/SrTiO 3 channels. Science 2020; 367:769-772. [PMID: 32054758 DOI: 10.1126/science.aat6467] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 10/23/2018] [Accepted: 01/14/2020] [Indexed: 11/02/2022]
Abstract
One-dimensional electronic systems can support exotic collective phases because of the enhanced role of electron correlations. We describe the experimental observation of a series of quantized conductance steps within strongly interacting electron waveguides formed at the lanthanum aluminate-strontium titanate (LaAlO3/SrTiO3) interface. The waveguide conductance follows a characteristic sequence within Pascal's triangle: (1, 3, 6, 10, 15, …) ⋅ e 2 /h, where e is the electron charge and h is the Planck constant. This behavior is consistent with the existence of a family of degenerate quantum liquids formed from bound states of n = 2, 3, 4, … electrons. Our experimental setup could provide a setting for solid-state analogs of a wide range of composite fermionic phases.
Collapse
Affiliation(s)
- Megan Briggeman
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA. .,Pittsburgh Quantum Institute, Pittsburgh, PA 15260, USA
| | - Michelle Tomczyk
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA.,Pittsburgh Quantum Institute, Pittsburgh, PA 15260, USA
| | - Binbin Tian
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA.,Pittsburgh Quantum Institute, Pittsburgh, PA 15260, USA
| | - Hyungwoo Lee
- Department of Materials Science and Engineering, University of Wisconsin, Madison, WI 53706, USA
| | - Jung-Woo Lee
- Department of Materials Science and Engineering, University of Wisconsin, Madison, WI 53706, USA
| | - Yuchi He
- Pittsburgh Quantum Institute, Pittsburgh, PA 15260, USA.,Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Anthony Tylan-Tyler
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA.,Pittsburgh Quantum Institute, Pittsburgh, PA 15260, USA
| | - Mengchen Huang
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA.,Pittsburgh Quantum Institute, Pittsburgh, PA 15260, USA
| | - Chang-Beom Eom
- Department of Materials Science and Engineering, University of Wisconsin, Madison, WI 53706, USA
| | - David Pekker
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA.,Pittsburgh Quantum Institute, Pittsburgh, PA 15260, USA
| | - Roger S K Mong
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA.,Pittsburgh Quantum Institute, Pittsburgh, PA 15260, USA
| | - Patrick Irvin
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA.,Pittsburgh Quantum Institute, Pittsburgh, PA 15260, USA
| | - Jeremy Levy
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA. .,Pittsburgh Quantum Institute, Pittsburgh, PA 15260, USA
| |
Collapse
|
6
|
Beygi A, Klevansky S, Lemmer R. Continuous quantum phase transition in the fermionic mass solutions of the Nambu–Jona-Lasinio model. Int J Clin Exp Med 2020. [DOI: 10.1103/physrevd.101.036005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
7
|
Moca CP, Chirla R, Dóra B, Zaránd G. Quantum Criticality and Formation of a Singular Fermi Liquid in the Attractive SU(N>2) Anderson Model. PHYSICAL REVIEW LETTERS 2019; 123:136803. [PMID: 31697511 DOI: 10.1103/physrevlett.123.136803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 08/12/2019] [Indexed: 06/10/2023]
Abstract
While much is known about repulsive quantum impurity models, significantly less attention has been devoted to their attractive counterparts. This motivated us to study the attractive SU(N) Anderson impurity model. While for the repulsive case the phase diagram features mild N dependence and the ground state is always a Fermi liquid, in the attractive case a Kosterlitz-Thouless charge localization phase transition is revealed for N>2. Beyond a critical value of attractive interaction, an abrupt jump appears in the number of particles at the impurity site, and a singular Fermi liquid state emerges, where the scattering of quasiparticles is found to exhibit power law behavior with fractional power. The capacity diverges exponentially at the quantum critical point, signaling the Kosterlitz-Thouless transition.
Collapse
Affiliation(s)
- Cătălin Paşcu Moca
- BME-MTA Exotic Quantum Phases Research Group, Institute of Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest, Hungary
- Department of Physics, University of Oradea, 410087 Oradea, Romania
| | - Razvan Chirla
- Department of Physics, University of Oradea, 410087 Oradea, Romania
- School of Medicine and Pharmacy, University of Oradea, 410087 Oradea, Romania
| | - Balázs Dóra
- Department of Theoretical Physics and MTA-BME Lendület Topology and Correlation Research Group, Budapest University of Technology and Economics, 1521 Budapest, Hungary
| | - Gergely Zaránd
- BME-MTA Exotic Quantum Phases Research Group, Institute of Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest, Hungary
| |
Collapse
|
8
|
Hattori K, Huang XG, Pisarski RD. Emergent QCD Kondo effect in two-flavor color superconducting phase. Int J Clin Exp Med 2019. [DOI: 10.1103/physrevd.99.094044] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
9
|
James AJA, Konik RM, Lecheminant P, Robinson NJ, Tsvelik AM. Non-perturbative methodologies for low-dimensional strongly-correlated systems: From non-Abelian bosonization to truncated spectrum methods. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:046002. [PMID: 29480168 DOI: 10.1088/1361-6633/aa91ea] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We review two important non-perturbative approaches for extracting the physics of low-dimensional strongly correlated quantum systems. Firstly, we start by providing a comprehensive review of non-Abelian bosonization. This includes an introduction to the basic elements of conformal field theory as applied to systems with a current algebra, and we orient the reader by presenting a number of applications of non-Abelian bosonization to models with large symmetries. We then tie this technique into recent advances in the ability of cold atomic systems to realize complex symmetries. Secondly, we discuss truncated spectrum methods for the numerical study of systems in one and two dimensions. For one-dimensional systems we provide the reader with considerable insight into the methodology by reviewing canonical applications of the technique to the Ising model (and its variants) and the sine-Gordon model. Following this we review recent work on the development of renormalization groups, both numerical and analytical, that alleviate the effects of truncating the spectrum. Using these technologies, we consider a number of applications to one-dimensional systems: properties of carbon nanotubes, quenches in the Lieb-Liniger model, 1 + 1D quantum chromodynamics, as well as Landau-Ginzburg theories. In the final part we move our attention to consider truncated spectrum methods applied to two-dimensional systems. This involves combining truncated spectrum methods with matrix product state algorithms. We describe applications of this method to two-dimensional systems of free fermions and the quantum Ising model, including their non-equilibrium dynamics.
Collapse
Affiliation(s)
- Andrew J A James
- London Centre for Nanotechnology, University College London, Gordon Street, London WC1H 0AH, United Kingdom
| | | | | | | | | |
Collapse
|
10
|
Dutta O, Gajda M, Hauke P, Lewenstein M, Lühmann DS, Malomed BA, Sowiński T, Zakrzewski J. Non-standard Hubbard models in optical lattices: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2015; 78:066001. [PMID: 26023844 DOI: 10.1088/0034-4885/78/6/066001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Originally, the Hubbard model was derived for describing the behavior of strongly correlated electrons in solids. However, for over a decade now, variations of it have also routinely been implemented with ultracold atoms in optical lattices, allowing their study in a clean, essentially defect-free environment. Here, we review some of the vast literature on this subject, with a focus on more recent non-standard forms of the Hubbard model. After giving an introduction to standard (fermionic and bosonic) Hubbard models, we discuss briefly common models for mixtures, as well as the so-called extended Bose-Hubbard models, that include interactions between neighboring sites, next-neighbor sites, and so on. The main part of the review discusses the importance of additional terms appearing when refining the tight-binding approximation for the original physical Hamiltonian. Even when restricting the models to the lowest Bloch band is justified, the standard approach neglects the density-induced tunneling (which has the same origin as the usual on-site interaction). The importance of these contributions is discussed for both contact and dipolar interactions. For sufficiently strong interactions, the effects related to higher Bloch bands also become important even for deep optical lattices. Different approaches that aim at incorporating these effects, mainly via dressing the basis, Wannier functions with interactions, leading to effective, density-dependent Hubbard-type models, are reviewed. We discuss also examples of Hubbard-like models that explicitly involve higher p orbitals, as well as models that dynamically couple spin and orbital degrees of freedom. Finally, we review mean-field nonlinear Schrödinger models of the Salerno type that share with the non-standard Hubbard models nonlinear coupling between the adjacent sites. In that part, discrete solitons are the main subject of consideration. We conclude by listing some open problems, to be addressed in the future.
Collapse
Affiliation(s)
- Omjyoti Dutta
- Instytut Fizyki imienia Mariana Smoluchowskiego, Uniwersytet Jagielloński, Łojasiewicza 11, 30-348 Kraków, Poland
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Nishida Y. Polaronic atom-trimer continuity in three-component Fermi gases. PHYSICAL REVIEW LETTERS 2015; 114:115302. [PMID: 25839286 DOI: 10.1103/physrevlett.114.115302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Indexed: 06/04/2023]
Abstract
Recently it has been proposed that three-component Fermi gases may exhibit a new type of crossover physics in which an unpaired Fermi sea of atoms smoothly evolves into that of trimers in addition to the ordinary BCS-BEC crossover of condensed pairs. Here we study its corresponding polaron problem in which a single impurity atom of one component interacts with condensed pairs of the other two components with equal populations. By developing a variational approach in the vicinity of a narrow Feshbach resonance, we show that the impurity atom smoothly changes its character from atom to trimer with increasing the attraction and eventually there is a sharp transition to dimer. The emergent polaronic atom-trimer continuity can be probed in ultracold atoms experiments by measuring the impurity spectral function. Our novel crossover wave function properly incorporating the polaronic atom-trimer continuity will provide a useful basis to further investigate the phase diagram of three-component Fermi gases in more general situations.
Collapse
Affiliation(s)
- Yusuke Nishida
- Department of Physics, Tokyo Institute of Technology, Ookayama, Meguro, Tokyo 152-8551, Japan
| |
Collapse
|
12
|
Cazalilla MA, Rey AM. Ultracold Fermi gases with emergent SU(N) symmetry. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2014; 77:124401. [PMID: 25429615 DOI: 10.1088/0034-4885/77/12/124401] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We review recent experimental and theoretical progress on ultracold alkaline-earth Fermi gases with emergent SU(N) symmetry. Emphasis is placed on describing the ground-breaking experimental achievements of recent years. The latter include (1) the cooling to below quantum degeneracy of various isotopes of ytterbium and strontium, (2) the demonstration of optical Feshbach resonances and the optical Stern-Gerlach effect, (3) the realization of a Mott insulator of (173)Yb atoms, (4) the creation of various kinds of Fermi-Bose mixtures and (5) the observation of many-body physics in optical lattice clocks. On the theory side, we survey the zoo of phases that have been predicted for both gases in a trap and loaded into an optical lattice, focusing on two and three dimensional systems. We also discuss some of the challenges that lie ahead for the realization of such phases such as reaching the temperature scale required to observe magnetic and more exotic quantum orders. The challenge of dealing with collisional relaxation of excited electronic levels is also discussed.
Collapse
Affiliation(s)
- Miguel A Cazalilla
- Department of Physics, National Tsing Hua University and National Center for Theoretical Sciences, Hsinchu City, Taiwan. Donostia International Physics Center (DIPC), Manuel de Lardizabal, 4. 20018 San Sebastian, Spain
| | | |
Collapse
|
13
|
Krauser JS, Ebling U, Fläschner N, Heinze J, Sengstock K, Lewenstein M, Eckardt A, Becker C. Giant Spin Oscillations in an Ultracold Fermi Sea. Science 2014; 343:157-60. [DOI: 10.1126/science.1244059] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- J. S. Krauser
- ILP (Institut für Laserphysik), Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - U. Ebling
- ICFO (Institut de Ciències Fotòniques), Avenida Carl Friedrich Gauss 3, 08860 Castelldefels, Spain
| | - N. Fläschner
- ILP (Institut für Laserphysik), Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - J. Heinze
- ILP (Institut für Laserphysik), Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - K. Sengstock
- ILP (Institut für Laserphysik), Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- ZOQ (Zentrum für Optische Quantentechnologien), Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - M. Lewenstein
- ICFO (Institut de Ciències Fotòniques), Avenida Carl Friedrich Gauss 3, 08860 Castelldefels, Spain
- ICREA (Institució Catalana de Recerca i Estudis Avançats), Lluís Companys 23, 08010 Barcelona, Spain
| | - A. Eckardt
- MPI-PKS (Max-Planck-Institut für Physik komplexer Systeme), Nöthnitzer Straße 38, 01187 Dresden, Germany
| | - C. Becker
- ILP (Institut für Laserphysik), Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- ZOQ (Zentrum für Optische Quantentechnologien), Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| |
Collapse
|
14
|
de Paz A, Sharma A, Chotia A, Maréchal E, Huckans JH, Pedri P, Santos L, Gorceix O, Vernac L, Laburthe-Tolra B. Nonequilibrium quantum magnetism in a dipolar lattice gas. PHYSICAL REVIEW LETTERS 2013; 111:185305. [PMID: 24237534 DOI: 10.1103/physrevlett.111.185305] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 09/06/2013] [Indexed: 06/02/2023]
Abstract
We report on the realization of quantum magnetism using a degenerate dipolar gas in an optical lattice. Our system implements a lattice model resembling the celebrated t-J model. It is characterized by a nonequilibrium spinor dynamics resulting from intersite Heisenberg-like spin-spin interactions provided by nonlocal dipole-dipole interactions. Moreover, due to its large spin, our chromium lattice gases constitute an excellent environment for the study of quantum magnetism of high-spin systems, as illustrated by the complex spin dynamics observed for doubly occupied sites.
Collapse
Affiliation(s)
- A de Paz
- Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, F-93430 Villetaneuse, France and CNRS, UMR 7538, LPL, F-93430 Villetaneuse, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Heinze J, Krauser JS, Fläschner N, Sengstock K, Becker C, Ebling U, Eckardt A, Lewenstein M. Engineering spin waves in a high-spin ultracold Fermi gas. PHYSICAL REVIEW LETTERS 2013; 110:250402. [PMID: 23829716 DOI: 10.1103/physrevlett.110.250402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Indexed: 06/02/2023]
Abstract
We report on the detailed study of multicomponent spin waves in an s=3/2 Fermi gas where the high spin leads to novel tensorial degrees of freedom compared to s=1/2 systems. The excitations of a spin-nematic state are investigated from the linear to the nonlinear regime, where the tensorial character is particularly pronounced. By tuning the initial state we engineer the tensorial spin-wave character, such that the magnitude and the sign of the counterflow spin currents are effectively controlled. A comparison of our data with numerical and analytical results shows good agreement.
Collapse
Affiliation(s)
- J Heinze
- Institut für Laser-Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Nishida Y. New type of crossover physics in three-component Fermi gases. PHYSICAL REVIEW LETTERS 2012; 109:240401. [PMID: 23368290 DOI: 10.1103/physrevlett.109.240401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Indexed: 06/01/2023]
Abstract
A three-component Fermi gas near a broad Feshbach resonance does not have a universal ground state due to the Thomas collapse, while it does near a narrow Feshbach resonance. We explore its universal phase diagram in the plane of the inverse scattering length 1/ak(F) and the resonance range R(*)k(F). For a large R(*)k(F), there exists a Lifshitz transition between superfluids with and without an unpaired Fermi surface as a function of 1/ak(F). With decreasing R(*)k(F), the Fermi surface coexisting with the superfluid can change smoothly from that of atoms to trimers ("atom-trimer continuity"), corresponding to the quark-hadron continuity in a dense nuclear matter. Eventually, there appears a finite window in 1/ak(F) where the superfluid is completely depleted by the trimer Fermi gas, which gives rise to a pair of quantum critical points. The boundaries of these three quantum phases are determined in regions where controlled analyses are possible and are also evaluated based on a mean-field plus trimer model.
Collapse
Affiliation(s)
- Yusuke Nishida
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| |
Collapse
|
17
|
Sornborger AT. Quantum simulation of tunneling in small systems. Sci Rep 2012; 2:597. [PMID: 22916333 PMCID: PMC3424524 DOI: 10.1038/srep00597] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 08/01/2012] [Indexed: 11/13/2022] Open
Abstract
A number of quantum algorithms have been performed on small quantum computers; these include Shor's prime factorization algorithm, error correction, Grover's search algorithm and a number of analog and digital quantum simulations. Because of the number of gates and qubits necessary, however, digital quantum particle simulations remain untested. A contributing factor to the system size required is the number of ancillary qubits needed to implement matrix exponentials of the potential operator. Here, we show that a set of tunneling problems may be investigated with no ancillary qubits and a cost of one single-qubit operator per time step for the potential evolution, eliminating at least half of the quantum gates required for the algorithm and more than that in the general case. Such simulations are within reach of current quantum computer architectures.
Collapse
Affiliation(s)
- Andrew T Sornborger
- Department of Mathematics and College of Engineering, University of Georgia, Athens, Georgia 30602, USA.
| |
Collapse
|
18
|
Inaba K, Suga SI. Superfluid state of repulsively interacting three-component fermionic atoms in optical lattices. PHYSICAL REVIEW LETTERS 2012; 108:255301. [PMID: 23004614 DOI: 10.1103/physrevlett.108.255301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 04/27/2012] [Indexed: 06/01/2023]
Abstract
We investigate the superfluid state of repulsively interacting three-component (color) fermionic atoms in optical lattices. When the anisotropy of the three repulsive interactions is strong, atoms of two of the three colors form Cooper pairs and atoms of the third color remain a Fermi liquid. An effective attractive interaction is induced by density fluctuations of the third-color atoms. This superfluid state is stable against changes in filling close to half filling. We determine the phase diagrams in terms of temperature, filling, and the anisotropy of the repulsive interactions.
Collapse
Affiliation(s)
- Kensuke Inaba
- NTT Basic Research Laboratories, NTT Corporation, Atsugi 243-0198, Japan
| | | |
Collapse
|
19
|
Affiliation(s)
- Stephen P Jordan
- Applied and Computational Mathematics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
| | | | | |
Collapse
|
20
|
The BCS–BEC Crossover and the Unitary Fermi Gas. THE BCS-BEC CROSSOVER AND THE UNITARY FERMI GAS 2012. [DOI: 10.1007/978-3-642-21978-8_1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
21
|
|
22
|
Costa L, Brachmann J, Voigt AC, Hahn C, Taglieber M, Hänsch TW, Dieckmann K. s-Wave interaction in a two-species Fermi-Fermi mixture at a narrow Feshbach resonance. PHYSICAL REVIEW LETTERS 2010; 105:123201. [PMID: 20867635 DOI: 10.1103/physrevlett.105.123201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Indexed: 05/29/2023]
Abstract
We investigate s-wave interactions in a two-species Fermi-Fermi mixture of 6Li and 40K. We develop for this case the method of cross-dimensional relaxation and find from a kinetic model, Monte Carlo simulations, and measurements that the individual relaxation rates differ due to the mass difference. The method is applied to measure the elastic cross section at the Feshbach resonance that we previously used for the production of heteronuclear molecules. Location (B0=155.09(5) G) and width are determined for this resonance. This reveals that molecules are being produced on the atomic side of the resonance within a range related to the Fermi energies, therefore establishing the first observation of a many body effect in the crossover regime of a narrow Feshbach resonance.
Collapse
Affiliation(s)
- L Costa
- Department für Physik der Ludwig-Maximilians-Universität, Schellingstraße 4, 80799 Munich, Germany
| | | | | | | | | | | | | |
Collapse
|
23
|
Crépin F, Zaránd G, Simon P. Disordered one-dimensional bose-fermi mixtures: the Bose-Fermi glass. PHYSICAL REVIEW LETTERS 2010; 105:115301. [PMID: 20867581 DOI: 10.1103/physrevlett.105.115301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Indexed: 05/29/2023]
Abstract
We analyze an interacting Bose-Fermi mixture in a 1D disordered potential by using a combination of renormalization group and variational methods. We obtain the complete phase diagram in the incommensurate case as a function of bosonic and interspecies interaction strengths, in the weak disorder limit. We find that the system is characterized by several phase transitions between superfluid and various glassy insulating states, including a new Bose-Fermi glass phase, where both species are coupled and localized. We show that the dynamical structure factor, as measured through Bragg scattering experiments, can distinguish between the various localized phases and probe their dynamics.
Collapse
Affiliation(s)
- François Crépin
- Laboratoire de Physique des Solides, CNRS UMR-8502 Université Paris Sud, 91405 Orsay Cedex, France
| | | | | |
Collapse
|
24
|
Rodríguez K, Argüelles A, Colomé-Tatché M, Vekua T, Santos L. Mott-insulator phases of spin-3/2 fermions in the presence of quadratic Zeeman coupling. PHYSICAL REVIEW LETTERS 2010; 105:050402. [PMID: 20867897 DOI: 10.1103/physrevlett.105.050402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Revised: 06/03/2010] [Indexed: 05/29/2023]
Abstract
We study the influence of the quadratic Zeeman effect on the Mott-insulator phases of hard-core 1D spin-3/2 fermions. We show that, contrary to spinor bosons, the quadratic Zeeman coupling preserves an SU(2)⊗SU(2) symmetry, leading for large-enough quadratic Zeeman coupling to an isotropic pseudo-spin-1/2 Heisenberg antiferromagnet. Decreasing the quadratic Zeeman coupling, this phase undergoes, depending on the scattering lengths, either a Kosterlitz-Thouless transition into a gapped dimerized phase or a commensurate-incommensurate transition into a gapless spin liquid. This rich phase diagram can be observed experimentally in four-component fermions in optical lattices under similar entropy constraints to those needed for Néel order in spin-1/2 gases.
Collapse
Affiliation(s)
- K Rodríguez
- Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstrasse 2 D-30167, Hannover, Germany
| | | | | | | | | |
Collapse
|
25
|
Kantian A, Dalmonte M, Diehl S, Hofstetter W, Zoller P, Daley AJ. Atomic color superfluid via three-body loss. PHYSICAL REVIEW LETTERS 2009; 103:240401. [PMID: 20366187 DOI: 10.1103/physrevlett.103.240401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 11/13/2009] [Indexed: 05/29/2023]
Abstract
Large three-body loss rates in a three-component Fermi gas confined in an optical lattice can dynamically prevent atoms from tunneling so as to occupy a lattice site with three atoms. This effective constraint not only suppresses the occurrence of actual loss events, but stabilizes BCS-pairing phases by suppressing the formation of trions. We study the effect of the constraint on the many-body physics using bosonization and density matrix renormalization group techniques, and also investigate the full dissipative dynamics including loss for the example of 6Li.
Collapse
Affiliation(s)
- A Kantian
- Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria
| | | | | | | | | | | |
Collapse
|
26
|
Williams JR, Hazlett EL, Huckans JH, Stites RW, Zhang Y, O'Hara KM. Evidence for an excited-state Efimov trimer in a three-component Fermi gas. PHYSICAL REVIEW LETTERS 2009; 103:130404. [PMID: 19905496 DOI: 10.1103/physrevlett.103.130404] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Indexed: 05/28/2023]
Abstract
We observe enhanced three-body recombination in a three-component ;{6}Li Fermi gas attributable to an excited Efimov trimer state intersecting the three-atom scattering threshold near 895 G. From measurements of the recombination rate we determine the Efimov parameters kappa_{*} and eta_{*} for the universal region above 600 G which includes three overlapping Feshbach resonances. The value of kappa_{*} also predicts the locations of loss features previously observed near 130 and 500 G [T. B. Ottenstein, Phys. Rev. Lett. 101, 203202 (2008)10.1103/PhysRevLett.101.203202; J. H. Huckans, Phys. Rev. Lett. 102, 165302 (2009)10.1103/PhysRevLett.102.165302] suggesting they are associated with a ground-state Efimov trimer near threshold. We also report on the realization of a degenerate three-component Fermi gas with approximate SU(3) symmetry.
Collapse
Affiliation(s)
- J R Williams
- Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802-6300, USA
| | | | | | | | | | | |
Collapse
|
27
|
D'Incao JP, Esry BD. Ultracold three-body collisions near overlapping Feshbach resonances. PHYSICAL REVIEW LETTERS 2009; 103:083202. [PMID: 19792726 DOI: 10.1103/physrevlett.103.083202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Indexed: 05/28/2023]
Abstract
We present a comprehensive collection of ultracold three-body collisions properties near overlapping Feshbach resonances. Our results incorporate variations of all scattering lengths and demonstrate novel collisional behavior, such as atom-molecule interference effects. Taking advantage of the unique ways in which these collisions reflect Efimov physics, new pathways to control atomic and molecular losses open up. Further, we show that overlapping resonances can greatly improve the chances of observing multiple Efimov features in an ultracold quantum gas for nearly any system.
Collapse
Affiliation(s)
- J P D'Incao
- JILA, University of Colorado, Boulder, Colorado 80309-0440, USA
| | | |
Collapse
|
28
|
Maeda K, Baym G, Hatsuda T. Simulating dense QCD matter with ultracold atomic boson-fermion mixtures. PHYSICAL REVIEW LETTERS 2009; 103:085301. [PMID: 19792735 DOI: 10.1103/physrevlett.103.085301] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 06/09/2009] [Indexed: 05/28/2023]
Abstract
We delineate, as an analog of two-flavor dense quark matter, the phase structure of a many-body mixture of atomic bosons and fermions in two internal states with a tunable boson-fermion attraction. The bosons b correspond to diquarks, and the fermions f to unpaired quarks. For weak b-f attraction, the system is a mixture of a Bose-Einstein condensate and degenerate fermions, while for strong attraction composite b-f fermions N, analogs of the nucleon, are formed, which are superfluid due to the N-N attraction in the spin-singlet channel. We determine the symmetry breaking patterns at finite temperature as a function of the b-f coupling strength, and relate the phase diagram to that of dense QCD.
Collapse
Affiliation(s)
- Kenji Maeda
- Department of Physics, University of Tokyo, Tokyo 113-0033, Japan
| | | | | |
Collapse
|
29
|
Naidon P, Ueda M. Possible efimov trimer state in a three-hyperfine-component lithium-6 mixture. PHYSICAL REVIEW LETTERS 2009; 103:073203. [PMID: 19792642 DOI: 10.1103/physrevlett.103.073203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Indexed: 05/28/2023]
Abstract
We consider the Efimov trimer theory as a possible framework to explain recently observed losses by inelastic three-body collisions in a three-hyperfine-component ultracold mixture of lithium 6. Within this framework, these losses would arise chiefly from the existence of an Efimov trimer bound state below the continuum of free triplets of atoms, and the loss maxima (at certain values of an applied magnetic field) would correspond to zero-energy resonances where the trimer dissociates into three free atoms. Our results show that such a trimer state is indeed possible given the two-body scattering lengths in the three-component lithium mixture and gives rise to two zero-energy resonances. The locations of these resonances appear to be consistent with observed losses.
Collapse
Affiliation(s)
- Pascal Naidon
- ERATO Macroscopic Quantum Project, JST, Tokyo 113-0033, Japan.
| | | |
Collapse
|
30
|
Huckans JH, Williams JR, Hazlett EL, Stites RW, O'Hara KM. Three-body recombination in a three-state Fermi gas with widely tunable interactions. PHYSICAL REVIEW LETTERS 2009; 102:165302. [PMID: 19518723 DOI: 10.1103/physrevlett.102.165302] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Revised: 03/17/2009] [Indexed: 05/27/2023]
Abstract
We investigate the stability of a three spin state mixture of ultracold fermionic 6Li atoms over a range of magnetic fields encompassing three Feshbach resonances. For most field values, we attribute decay of the atomic population to three-body processes involving one atom from each spin state and find that the three-body loss coefficient varies by over 4 orders of magnitude. We observe high stability when at least two of the three scattering lengths are small, rapid loss near the Feshbach resonances, and two unexpected resonant loss features. At our highest fields, where all pairwise scattering lengths are approaching a_{t}=-2140a_{0}, we measure a three-body loss coefficient L_{3} approximately 5x10;{-22} cm;{6}/s and a trend toward lower decay rates for higher fields indicating that future studies of color superfluidity and trion formation in a SU(3) symmetric Fermi gas may be feasible.
Collapse
Affiliation(s)
- J H Huckans
- Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802-6300, USA
| | | | | | | | | |
Collapse
|
31
|
Daley AJ, Taylor JM, Diehl S, Baranov M, Zoller P. Atomic three-body loss as a dynamical three-body interaction. PHYSICAL REVIEW LETTERS 2009; 102:040402. [PMID: 19257406 DOI: 10.1103/physrevlett.102.040402] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Indexed: 05/27/2023]
Abstract
We discuss how large three-body loss of atoms in an optical lattice can give rise to effective hard-core three-body interactions. For bosons, in addition to the usual atomic superfluid, a dimer superfluid can then be observed for attractive two-body interactions. The nonequilibrium dynamics of preparation and stability of these phases are studied in 1D by combining time-dependent density matrix renormalization group techniques with a quantum trajectories method.
Collapse
Affiliation(s)
- A J Daley
- Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria
| | | | | | | | | |
Collapse
|
32
|
Voigt AC, Taglieber M, Costa L, Aoki T, Wieser W, Hänsch TW, Dieckmann K. Ultracold heteronuclear fermi-fermi molecules. PHYSICAL REVIEW LETTERS 2009; 102:020405. [PMID: 19257253 DOI: 10.1103/physrevlett.102.020405] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Indexed: 05/27/2023]
Abstract
We report on the first creation of ultracold bosonic heteronuclear molecules of two fermionic species, 6Li and 40K, by a magnetic field sweep across an interspecies s-wave Feshbach resonance. This allows us to associate up to 4x10(4) molecules with high efficiencies of up to 50%. Using direct imaging of the molecules, we measure increased lifetimes of the molecules close to resonance of more than 100 ms in the molecule-atom mixture stored in a harmonic trap.
Collapse
Affiliation(s)
- A-C Voigt
- Department für Physik der Ludwig-Maximilians-Universität, Schellingstrasse 4, 80799 Munich, Germany.
| | | | | | | | | | | | | |
Collapse
|
33
|
Ottenstein TB, Lompe T, Kohnen M, Wenz AN, Jochim S. Collisional stability of a three-component degenerate fermi gas. PHYSICAL REVIEW LETTERS 2008; 101:203202. [PMID: 19113336 DOI: 10.1103/physrevlett.101.203202] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Indexed: 05/27/2023]
Abstract
We report on the creation of a degenerate Fermi gas consisting of a balanced mixture of atoms in three different hyperfine states of 6Li. This new system consists of three distinguishable fermions with different and tunable interparticle scattering lengths a_{12}, a_{13}, and a_{23}. We are able to prepare samples containing 5x10;{4} atoms in each state at a temperature of about 215 nK, which corresponds to T/T_{F} approximately 0.37. We investigated the collisional stability of the gas for magnetic fields between 0 and 600 G and found a prominent loss feature at 130 G. From lifetime measurements, we determined three-body loss coefficients, which vary over nearly 3 orders of magnitude.
Collapse
Affiliation(s)
- T B Ottenstein
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
| | | | | | | | | |
Collapse
|
34
|
Bornemann N, Hyllus P, Santos L. Resonant spin-changing collisions in spinor fermi gases. PHYSICAL REVIEW LETTERS 2008; 100:205302. [PMID: 18518551 DOI: 10.1103/physrevlett.100.205302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Revised: 04/14/2008] [Indexed: 05/26/2023]
Abstract
The compensation of quadratic Zeeman effect and trap energy in high-spin fermions is shown to lead to resonances in the spin-changing collisions that are typically absent in spinor condensates and spin-1/2 fermions. We study these resonances in lattice fermions, showing that they permit the targeting of a particular spin-changing channel while suppressing the rest and the creation of magnetically insensitive superpositions of many-body states with entangled spin and trap degrees of freedom. Finally, the intersite tunneling may lead to a quantum phase transition described by a quantum Ising model.
Collapse
Affiliation(s)
- N Bornemann
- Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstrasee 2, D-30167, Hannover, Germany
| | | | | |
Collapse
|
35
|
Guan XW, Batchelor MT, Lee C, Zhou HQ. Magnetic phase transitions in one-dimensional strongly attractive three-component ultracold fermions. PHYSICAL REVIEW LETTERS 2008; 100:200401. [PMID: 18518509 DOI: 10.1103/physrevlett.100.200401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Revised: 12/23/2007] [Indexed: 05/26/2023]
Abstract
We investigate the nature of trions, pairing, and quantum phase transitions in one-dimensional strongly attractive three-component ultracold fermions in external fields. Exact results for the ground-state energy, critical fields, magnetization and phase diagrams are obtained analytically from the Bethe ansatz solutions. Driven by Zeeman splitting, the system shows exotic phases of trions, bound pairs, a normal Fermi liquid, and four mixtures of these states. Particularly, a smooth phase transition from a trionic phase into a pairing phase occurs as the highest hyperfine level separates from the two lower energy levels. In contrast, there is a smooth phase transition from the trionic phase into a normal Fermi liquid as the lowest level separates from the two higher levels.
Collapse
Affiliation(s)
- X W Guan
- Department of Theoretical Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200, Australia
| | | | | | | |
Collapse
|
36
|
Abstract
Ultracold quantum gases are proving to be a powerful model system for strongly interacting electronic many-body systems. This Perspective explores how such atomic ensembles can help to unravel some of the outstanding open questions in the field.
Collapse
|
37
|
Taglieber M, Voigt AC, Aoki T, Hänsch TW, Dieckmann K. Quantum degenerate two-species fermi-fermi mixture coexisting with a bose-einstein condensate. PHYSICAL REVIEW LETTERS 2008; 100:010401. [PMID: 18232744 DOI: 10.1103/physrevlett.100.010401] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Indexed: 05/25/2023]
Abstract
We report on the generation of a quantum degenerate Fermi-Fermi mixture of two different atomic species. The quantum degenerate mixture is realized employing sympathetic cooling of fermionic 6Li and 40K gases by an evaporatively cooled bosonic 87Rb gas. We describe the combination of trapping and cooling methods that proved crucial to successfully cool the mixture. In particular, we study the last part of the cooling process and show that the efficiency of sympathetic cooling of the 6Li gas by 87Rb is increased by the presence of 40K through catalytic cooling. Because of the differing physical properties of the two components, the quantum degenerate 6Li-40K Fermi-Fermi mixture is an excellent candidate for a stable, heteronuclear system allowing the study of several so far unexplored types of quantum matter.
Collapse
Affiliation(s)
- M Taglieber
- Department für Physik der Ludwig-Maximilians-Universität, Schellingstrasse 4, 80799 Munich, Germany
| | | | | | | | | |
Collapse
|
38
|
Cherng RW, Refael G, Demler E. Superfluidity and magnetism in multicomponent ultracold fermions. PHYSICAL REVIEW LETTERS 2007; 99:130406. [PMID: 17930563 DOI: 10.1103/physrevlett.99.130406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Indexed: 05/25/2023]
Abstract
We study the interplay between superfluidity and magnetism in a multicomponent gas of ultracold fermions. Ward-Takahashi identities constrain possible mean-field states describing order parameters for both pairing and magnetization. The structure of global phase diagrams arises from competition among these states as functions of anisotropies in chemical potential, density, or interactions. They exhibit first and second order phase transition as well as multicritical points, metastability regions, and phase separation. We comment on experimental signatures in ultracold atoms.
Collapse
Affiliation(s)
- R W Cherng
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | | | | |
Collapse
|