901
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Paredes B, Cirac JI. From Cooper pairs to Luttinger liquids with bosonic atoms in optical lattices. PHYSICAL REVIEW LETTERS 2003; 90:150402. [PMID: 12732022 DOI: 10.1103/physrevlett.90.150402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2002] [Indexed: 05/24/2023]
Abstract
We propose a scheme to observe strongly correlated fermionic phenomena with bosonic atoms in optical lattices. For different values of the sign and strength of the scattering lengths, it is possible to reach either a "superconducting" regime, where the system exhibits atomic pairing, or a Luttinger liquid behavior. We identify the range of parameters where these phenomena appear, illustrate our predictions with numerical calculations, and show how to detect the presence of pairing.
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Affiliation(s)
- B Paredes
- Max-Planck Institute for Quantum Optics, Hans-Kopfermann Strasse 1, D-85748 Garching, Germany
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902
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Yi S, Müstecaplioğlu OE, You L. Quantum phase diffusions of a spinor condensate. PHYSICAL REVIEW LETTERS 2003; 90:140404. [PMID: 12731901 DOI: 10.1103/physrevlett.90.140404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2002] [Indexed: 05/24/2023]
Abstract
We discuss the quantum phases and their diffusion in a spinor-1 atomic Bose-Einstein condensate. For ferromagnetic interactions, we obtain the exact ground state distribution of the phase fluctuations corresponding to the total atom number (N), the magnetization (M), and the alignment (or hypercharge) (Y) of the system. The mean-field ground state is shown to be stable against these fluctuations, which dynamically recover the two continuous symmetries associated with the conservation of N and M as in current experiments.
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Affiliation(s)
- S Yi
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA
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903
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Mompart J, Eckert K, Ertmer W, Birkl G, Lewenstein M. Quantum computing with spatially delocalized qubits. PHYSICAL REVIEW LETTERS 2003; 90:147901. [PMID: 12731947 DOI: 10.1103/physrevlett.90.147901] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2002] [Indexed: 05/24/2023]
Abstract
We analyze the operation of quantum gates for neutral atoms with qubits that are delocalized in space, i.e., the computational basis states are defined by the presence of a neutral atom in the ground state of one out of two trapping potentials. The implementation of single-qubit gates as well as a controlled phase gate between two qubits is discussed and explicit calculations are presented for rubidium atoms in optical microtraps. Furthermore, we show how multiqubit highly entangled states can be created in this scheme.
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Affiliation(s)
- J Mompart
- Institute of Theoretical Physics, University of Hannover, Appelstrasse 2, D-30167 Hannover, Germany
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904
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Fort C, Cataliotti FS, Fallani L, Ferlaino F, Maddaloni P, Inguscio M. Collective excitations of a trapped Bose-Einstein condensate in the presence of a 1D optical lattice. PHYSICAL REVIEW LETTERS 2003; 90:140405. [PMID: 12731902 DOI: 10.1103/physrevlett.90.140405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2002] [Indexed: 05/24/2023]
Abstract
We study low-lying collective modes of an elongated 87Rb condensate produced in a 3D magnetic harmonic trap with the addition of a 1D periodic potential which is provided by a laser standing wave along the axial direction. While the transverse breathing mode remains unperturbed, quadrupole and dipole oscillations along the optical lattice are strongly modified. Precise measurements of the collective mode frequencies at different heights of the optical barriers provide a stringent test of the theoretical model recently introduced [M. Krämer, Phys. Rev. Lett. 88, 180404 (2002)]].
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Affiliation(s)
- C Fort
- LENS, Dipartimento di Fisica, Università di Firenze and Istituto Nazionale per la Fisica della Materia, via Nello Carrara 1, I-50019 Sesto Fiorentino (Florence), Italy
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905
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Büchler HP, Blatter G, Zwerger W. Commensurate-incommensurate transition of cold atoms in an optical lattice. PHYSICAL REVIEW LETTERS 2003; 90:130401. [PMID: 12689270 DOI: 10.1103/physrevlett.90.130401] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2002] [Indexed: 05/24/2023]
Abstract
An atomic gas subject to a commensurate periodic potential generated by an optical lattice undergoes a superfluid-Mott insulator transition. Confining a strongly interacting gas to one dimension generates an instability where an arbitrary weak potential is sufficient to pin the atoms into the Mott state; here, we derive the corresponding phase diagram. The commensurate pinned state may be detected via its finite excitation gap and the Bragg peaks in the static structure factor.
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Affiliation(s)
- H P Büchler
- Theoretische Physik, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
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906
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Recati A, Fedichev PO, Zwerger W, Zoller P. Fermi one-dimensional quantum gas: Luttinger liquid approach and spin charge separation. ACTA ACUST UNITED AC 2003. [DOI: 10.1088/1464-4266/5/2/359] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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907
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Hensinger WK, Heckenberg NR, Milburn GJ, Rubinsztein-Dunlop H. Experimental tests of quantum nonlinear dynamics in atom optics. ACTA ACUST UNITED AC 2003. [DOI: 10.1088/1464-4266/5/2/202] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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908
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909
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910
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M ller JH, Morsch O, Cristiani M, Ciampini D, Arimondo E. Hitting Bose Einstein condensates with a comb: evolution of interference patterns inside a magnetic trap. ACTA ACUST UNITED AC 2003. [DOI: 10.1088/1464-4266/5/2/356] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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911
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Cataliotti FS, Fallani L, Ferlaino F, Fort C, Maddaloni P, Inguscio M. Dynamics of a trapped Bose Einstein condensate in the presence of a one-dimensional optical lattice. ACTA ACUST UNITED AC 2003. [DOI: 10.1088/1464-4266/5/2/353] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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912
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Mouchet A, Delande D. Signatures of chaotic tunneling. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 67:046216. [PMID: 12786469 DOI: 10.1103/physreve.67.046216] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2002] [Indexed: 05/24/2023]
Abstract
Recent experiments with cold atoms provide a significant step toward a better understanding of tunneling when irregular dynamics is present at the classical level. In this paper, we lay out numerical studies that shed light on the previous experiments and help to clarify the underlying physics. This study also provides guidelines for future experiments.
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Affiliation(s)
- Amaury Mouchet
- Laboratoire de Mathématiques et de Physique Théorique, Université François Rabelais, Avenue Monge, Parc de Grandmont 37200 Tours, France.
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913
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García-Ripoll JJ, Cirac JI. Quantum computation with unknown parameters. PHYSICAL REVIEW LETTERS 2003; 90:127902. [PMID: 12688900 DOI: 10.1103/physrevlett.90.127902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2002] [Indexed: 05/24/2023]
Abstract
We show how it is possible to realize quantum computations on a system in which most of the parameters are practically unknown. We illustrate our results with a novel implementation of a quantum computer by means of bosonic atoms in an optical lattice. In particular, we show how a universal set of gates can be carried out even if the number of atoms per site is uncertain.
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Affiliation(s)
- J J García-Ripoll
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
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914
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Damski B, Santos L, Tiemann E, Lewenstein M, Kotochigova S, Julienne P, Zoller P. Creation of a dipolar superfluid in optical lattices. PHYSICAL REVIEW LETTERS 2003; 90:110401. [PMID: 12688917 DOI: 10.1103/physrevlett.90.110401] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2002] [Indexed: 05/24/2023]
Abstract
We show that, by loading a Bose-Einstein condensate of two different atomic species into an optical lattice, it is possible to achieve a Mott-insulator phase with exactly one atom of each species per lattice site. A subsequent photoassociation leads to the formation of one heteronuclear molecule with a large electric dipole moment, at each lattice site. The melting of such a dipolar Mott insulator creates a dipolar superfluid, and eventually a dipolar molecular condensate.
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Affiliation(s)
- B Damski
- Institut für Theoretische Physik, Universität Hannover, Germany
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915
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Mølmer K. Jaynes-Cummings dynamics with a matter wave oscillator. PHYSICAL REVIEW LETTERS 2003; 90:110403. [PMID: 12688919 DOI: 10.1103/physrevlett.90.110403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2002] [Indexed: 05/24/2023]
Abstract
We propose to subject two Bose-Einstein condensates to a periodic potential, so that one condensate undergoes the Mott-insulator transition to a state with precisely one atom per lattice site. We show that photoassociation of heteronuclear molecules within each lattice site is described by the quantum optical Jaynes-Cummings Hamiltonian. In analogy with studies of this Hamiltonian with cavity fields and trapped ions, we are thus able to engineer quantum optical states of atomic matter wave fields and we are able to reconstruct these states by quantum state tomography.
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Affiliation(s)
- Klaus Mølmer
- QUANTOP, Danish National Research Foundation Center for Quantum Optics, Department of Physics and Astronomy, University of Aarhus, DK-8000 Arhus C, Denmark
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916
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Scott RG, Martin AM, Fromhold TM, Bujkiewicz S, Sheard FW, Leadbeater M. Creation of solitons and vortices by bragg reflection of Bose-Einstein condensates in an optical lattice. PHYSICAL REVIEW LETTERS 2003; 90:110404. [PMID: 12688920 DOI: 10.1103/physrevlett.90.110404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2002] [Indexed: 05/24/2023]
Abstract
We study the dynamics of Bose-Einstein condensates in an optical lattice and harmonic trap. The condensates are set in motion by displacing the trap and initially follow simple semiclassical paths, shaped by the lowest energy band. Above a critical displacement, the condensate undergoes Bragg reflection. For high atom densities, the first Bragg reflection generates a train of solitons and vortices, which destabilize the condensate and trigger explosive expansion. At lower densities, soliton and vortex formation requires multiple Bragg reflections, and damps the center-of-mass motion.
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Affiliation(s)
- R G Scott
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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917
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Kuklov AB, Svistunov BV. Counterflow superfluidity of two-species ultracold atoms in a commensurate optical lattice. PHYSICAL REVIEW LETTERS 2003; 90:100401. [PMID: 12688982 DOI: 10.1103/physrevlett.90.100401] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2002] [Indexed: 05/24/2023]
Abstract
In the Mott-insulator regime, two species of ultracold atoms in an optical lattice can exhibit the low-energy counterflow motion. We construct effective Hamiltonians for the three classes of the two-species (fermion-fermion, boson-boson, and boson-fermion-type) insulators and reveal the conditions when the resulting ground state supports super-counter-fluidity (SCF), with the alternative being phase segregation. We emphasize a crucial role of breaking the isotopic symmetry between the species for realizing the SCF phase.
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Affiliation(s)
- A B Kuklov
- The College of Staten Island, CUNY, Staten Island, New York 10314, USA
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918
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Ellmann H, Jersblad J, Kastberg A. Experiments with a 3D double optical lattice. PHYSICAL REVIEW LETTERS 2003; 90:053001. [PMID: 12633348 DOI: 10.1103/physrevlett.90.053001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2002] [Indexed: 05/24/2023]
Abstract
We present a setup where we trap two different cesium hyperfine ground states in two different near-resonant optical lattices with identical topographies. We demonstrate that we can change the relative spatial phase between the lattices and we measure the equilibrium temperature as a function of the relative spatial phase. This provides a topographical chart of the optical potential. We also determine the rate at which atoms are transferred between the lattices and show that the setup is a promising candidate for implementing coherent quantum state manipulation.
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919
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You L. Creating maximally entangled atomic states in a Bose-Einstein condensate. PHYSICAL REVIEW LETTERS 2003; 90:030402. [PMID: 12570474 DOI: 10.1103/physrevlett.90.030402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2002] [Indexed: 05/24/2023]
Abstract
We propose a protocol to create maximally entangled pairs, triplets, quartiles, and other clusters of Bose-condensed atoms starting from a condensate in the Mott insulator state. The essential element is to drive single atom Raman transitions using laser pulses. Our scheme is simple, efficient, and can be readily applied to the recent experimental system as reported by M. Greiner 413, 44 (2002)].
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Affiliation(s)
- L You
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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920
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Fleischer JW, Carmon T, Segev M, Efremidis NK, Christodoulides DN. Observation of discrete solitons in optically induced real time waveguide arrays. PHYSICAL REVIEW LETTERS 2003; 90:023902. [PMID: 12570547 DOI: 10.1103/physrevlett.90.023902] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2002] [Indexed: 05/24/2023]
Abstract
We report the first experimental observation of discrete solitons in an array of optically induced waveguides. The waveguide lattice is induced in real time by illuminating a photorefractive crystal with a pair of interfering plane waves. We demonstrate two types of bright discrete solitons: in-phase self-localized states and the staggered (pi out-of-phase) soliton family. This experiment is the first observation of bright staggered solitons in any physical system. Our scheme paves the way for reconfigurable focusing and defocusing photonic lattices where low-power (mW) discrete solitons can be thoroughly investigated.
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Affiliation(s)
- Jason W Fleischer
- Physics Department, Technion-Israel Institute of Technology, Haifa 32000, Israel
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921
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Abstract
Bose-Einstein condensation of cesium atoms is achieved by evaporative cooling using optical trapping techniques. The ability to tune the interactions between the ultracold atoms by an external magnetic field is crucial to obtain the condensate and offers intriguing features for potential applications. We explore various regimes of condensate self-interaction (attractive, repulsive, and null interaction strength) and demonstrate properties of imploding, exploding, and non-interacting quantum matter.
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Affiliation(s)
- Tino Weber
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrabetae 25, 6020 Innsbruck, Austria
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922
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923
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Marte A, Volz T, Schuster J, Dürr S, Rempe G, van Kempen EGM, Verhaar BJ. Feshbach resonances in rubidium 87: precision measurement and analysis. PHYSICAL REVIEW LETTERS 2002; 89:283202. [PMID: 12513142 DOI: 10.1103/physrevlett.89.283202] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2002] [Indexed: 05/24/2023]
Abstract
More than 40 Feshbach resonances in rubidium 87 are observed in the magnetic-field range between 0.5 and 1260 G for various spin mixtures in the lower hyperfine ground state. The Feshbach resonances are observed by monitoring the atom loss, and their positions are determined with an accuracy of 30 mG. In a detailed analysis, the resonances are identified and an improved set of model parameters for the rubidium interatomic potential is deduced. The elastic width of the broadest resonance at 1007 G is predicted to be significantly larger than the magnetic-field resolution of the apparatus. This demonstrates the potential for applications based on tuning the scattering length.
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Affiliation(s)
- A Marte
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
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924
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Jonsell S, Heiselberg H, Pethick CJ. Universal behavior of the energy of trapped few-boson systems with large scattering length. PHYSICAL REVIEW LETTERS 2002; 89:250401. [PMID: 12484868 DOI: 10.1103/physrevlett.89.250401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2002] [Indexed: 05/24/2023]
Abstract
We calculate energy levels of two and three bosons trapped in a harmonic oscillator potential with oscillator length a(osc). The atoms are assumed to interact through a short-range potential with a scattering length a, and the short-distance behavior of the three-body wave function is characterized by a parameter theta. For large positive a/a(osc), the energies of states that, in the absence of the trap, correspond to three free atoms approach values independent of a and theta. For other states, the theta dependence of the energy is strong, but the energy is independent of a for |a/a(osc)|>>1.
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Affiliation(s)
- S Jonsell
- NORDITA, Blegdamsvej 17, DK-2100 Copenhagen Ø, Denmark
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925
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Altman E, Auerbach A. Oscillating superfluidity of bosons in optical lattices. PHYSICAL REVIEW LETTERS 2002; 89:250404. [PMID: 12484871 DOI: 10.1103/physrevlett.89.250404] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2002] [Indexed: 05/24/2023]
Abstract
Following a suggestion by Orzel et al. [Science 291, 2386 (2001)]], we analyze bosons in an optical lattice undergoing a sudden parameter change from the Mott to superfluid phase. We introduce a modified coherent states path integral to describe both phases. The saddle point theory yields collective oscillations of the uniform superfluid order parameter. We calculate its damping rate by phason pair emission. In two dimensions the overdamped region largely overlaps with the quantum critical region. Measurements of critical dynamics on the Mott side are proposed.
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Affiliation(s)
- Ehud Altman
- Department of Physics, Technion, Haifa 32000, Israel
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926
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Ohberg P, Santos L. Dynamical transition from a quasi-one-dimensional Bose-Einstein condensate to a Tonks-Girardeau gas. PHYSICAL REVIEW LETTERS 2002; 89:240402. [PMID: 12484933 DOI: 10.1103/physrevlett.89.240402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2002] [Indexed: 05/24/2023]
Abstract
We analyze in detail the expansion of a 1D Bose gas after removing the axial confinement. We show that during its one-dimensional expansion the density of the Bose gas does not follow a self-similar solution. Our analysis is based on a nonlinear Schrödinger equation with variable nonlinearity whose validity is discussed for the expansion problem, by comparing with an exact Bose-Fermi mapping for the case of an initial Tonks-Girardeau gas. For this case, the gas is shown to expand self-similarly, with a different scaling law compared to the one-dimensional Thomas-Fermi condensate.
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Affiliation(s)
- P Ohberg
- School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife KY16 9SS, United Kingdom
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927
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Hofstetter W, Cirac JI, Zoller P, Demler E, Lukin MD. High-temperature superfluidity of fermionic atoms in optical lattices. PHYSICAL REVIEW LETTERS 2002; 89:220407. [PMID: 12485058 DOI: 10.1103/physrevlett.89.220407] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2002] [Indexed: 05/24/2023]
Abstract
Fermionic atoms confined in a potential created by standing wave light can undergo a phase transition to a superfluid state at a dramatically increased transition temperature. Depending upon carefully controlled parameters, a transition to a superfluid state of Cooper pairs, antiferromagnetic states or d-wave pairing states can be induced and probed under realistic experimental conditions. We describe an atomic physics experiment that can provide critical insight into the origin of high-temperature superconductivity in cuprates.
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Affiliation(s)
- W Hofstetter
- Physics Department, Harvard University, Cambridge, Massachusetts 02138, USA
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928
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Abstract
The past decade has seen dramatic progress in our ability to manipulate and coherently control the motion of atoms. This progress has both fundamental and applied importance. On the one hand, recent experiments are providing new perspectives for the study of quantum phase transitions and highly entangled quantum states. On the other hand, this exquisite control offers the prospect of a new generation of force sensors of unprecedented sensitivity and accuracy.
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Affiliation(s)
- Mark A Kasevich
- Department of Physics, Stanford University, Stanford, CA 94305-4060, USA
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929
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Smerzi A, Trombettoni A, Kevrekidis PG, Bishop AR. Dynamical superfluid-insulator transition in a chain of weakly coupled bose-Einstein condensates. PHYSICAL REVIEW LETTERS 2002; 89:170402. [PMID: 12398650 DOI: 10.1103/physrevlett.89.170402] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2001] [Indexed: 05/24/2023]
Abstract
We predict a dynamical classical superfluid-insulator transition in a Bose-Einstein condensate trapped in an optical and a magnetic potential. In the tight-binding limit, this system realizes an array of weakly coupled condensates driven by an external harmonic field. For small displacements of the parabolic trap about the equilibrium position, the condensates coherently oscillate in the array. For large displacements, the condensates remain localized on the side of the harmonic trap with a randomization of the relative phases. The superfluid-insulator transition is due to a discrete modulational instability, occurring when the condensate center of mass velocity is larger than a critical value.
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Affiliation(s)
- A Smerzi
- Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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930
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Dunningham JA, Burnett K, Barnett SM. Interferometry below the standard quantum limit with Bose-Einstein condensates. PHYSICAL REVIEW LETTERS 2002; 89:150401. [PMID: 12365974 DOI: 10.1103/physrevlett.89.150401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2002] [Indexed: 05/23/2023]
Abstract
We discuss a scheme for using entangled Bose-Einstein condensates to detect phase differences with a resolution better than the standard quantum limit. To date, schemes have shown that the enhancement in phase resolution gained by entangling condensates is lost when dissipation is present. Here we show how this can be overcome by using number correlated condensates, as have been produced recently in the laboratory. We also outline a scheme for measuring this phase that is not destroyed when the effects of finite detector efficiency are considered.
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Affiliation(s)
- J A Dunningham
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, United Kingdom
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931
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Batrouni GG, Rousseau V, Scalettar RT, Rigol M, Muramatsu A, Denteneer PJH, Troyer M. Mott domains of bosons confined on optical lattices. PHYSICAL REVIEW LETTERS 2002; 89:117203. [PMID: 12225165 DOI: 10.1103/physrevlett.89.117203] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2002] [Indexed: 05/23/2023]
Abstract
In the absence of a confining potential, the boson-Hubbard model exhibits a superfluid to Mott insulator quantum phase transition at commensurate fillings and strong coupling. We use quantum Monte Carlo simulations to study the ground state of the one-dimensional bosonic Hubbard model in a trap. Some, but not all, aspects of the Mott insulating phase persist. Mott behavior occurs for a continuous range of incommensurate fillings, very different from the unconfined case, and the establishment of the Mott phase does not proceed via a traditional quantum phase transition. These results have important implications for interpreting experiments on ultracold atoms on optical lattices.
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Affiliation(s)
- G G Batrouni
- Institut Non-Linéaire de Nice, Université de Nice-Sophia Antipolis, 1361 route des Lucioles, 06560 Valbonne, France
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932
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Greiner M, Mandel O, Hänsch TW, Bloch I. Collapse and revival of the matter wave field of a Bose-Einstein condensate. Nature 2002; 419:51-4. [PMID: 12214228 DOI: 10.1038/nature00968] [Citation(s) in RCA: 218] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A Bose-Einstein condensate represents the most 'classical' form of a matter wave, just as an optical laser emits the most classical form of an electromagnetic wave. Nevertheless, the matter wave field has a quantized structure owing to the granularity of the discrete underlying atoms. Although such a field is usually assumed to be intrinsically stable (apart from incoherent loss processes), this is no longer true when the condensate is in a coherent superposition of different atom number states. For example, in a Bose-Einstein condensate confined by a three-dimensional optical lattice, each potential well can be prepared in a coherent superposition of different atom number states, with constant relative phases between neighbouring lattice sites. It is then natural to ask how the individual matter wave fields and their relative phases evolve. Here we use such a set-up to investigate these questions experimentally, observing that the matter wave field of the Bose-Einstein condensate undergoes a periodic series of collapses and revivals; this behaviour is directly demonstrated in the dynamical evolution of the multiple matter wave interference pattern. We attribute the oscillations to the quantized structure of the matter wave field and the collisions between individual atoms.
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Affiliation(s)
- Markus Greiner
- Sektion Physik, Ludwig-Maximilians-Universität, Schellingstrasse 4/III, D-80799 Munich, Germany
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933
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Olshanii M, Weiss D. Producing Bose-Einstein condensates using optical lattices. PHYSICAL REVIEW LETTERS 2002; 89:090404. [PMID: 12190384 DOI: 10.1103/physrevlett.89.090404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2002] [Indexed: 05/23/2023]
Abstract
We relate the entropies of ensembles of atoms in optical lattices to atoms in simple traps. We then determine which ensembles of lattice-bound atoms will adiabatically transform into a Bose condensate. This shows a feasible approach to Bose condensation without evaporative cooling.
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Affiliation(s)
- Maxim Olshanii
- Department of Physics & Astronomy, University of Southern California, Los Angeles, California 90089-0484, USA.
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934
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Dumke R, Volk M, Müther T, Buchkremer FBJ, Birkl G, Ertmer W. Micro-optical realization of arrays of selectively addressable dipole traps: a scalable configuration for quantum computation with atomic qubits. PHYSICAL REVIEW LETTERS 2002; 89:097903. [PMID: 12190441 DOI: 10.1103/physrevlett.89.097903] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2001] [Indexed: 05/23/2023]
Abstract
We experimentally demonstrate novel structures for the realization of registers of atomic qubits: We trap neutral atoms in one- and two-dimensional arrays of far-detuned dipole traps obtained by focusing a red-detuned laser beam with a microfabricated array of microlenses. We are able to selectively address individual trap sites due to their large lateral separation of 125 microm. We initialize and read out different internal states for the individual sites. We also create two interleaved sets of trap arrays with adjustable separation, as required for many proposed implementations of quantum gate operations.
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Affiliation(s)
- R Dumke
- Institut für Quantenoptik, Universität Hannover, Welfengarten 1, D-30167 Hannover, Germany
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935
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936
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Ho TL, Mueller EJ. Rotating spin-1 bose clusters. PHYSICAL REVIEW LETTERS 2002; 89:050401. [PMID: 12144428 DOI: 10.1103/physrevlett.89.050401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2002] [Indexed: 05/23/2023]
Abstract
We propose a simple scheme for generating rotating atomic clusters in an optical lattice which produces states with quantum Hall and spin liquid properties. As the rotation frequencies increase, the ground state of a rotating cluster of spin-1 Bose atoms undergoes a sequence of (spin and orbit) transitions, which terminates at an angular momentum L(*) substantially lower than that of the boson Laughlin state. The spin-orbit correlations reflect "fermionization" of bosons facilitated by their spin degrees of freedom. We also show that the density of an expanding group of clusters has a scaling form which reveals the quantum Hall and spin structure of a single cluster.
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Affiliation(s)
- Tin-Lun Ho
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
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937
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Jaksch D, Venturi V, Cirac JI, Williams CJ, Zoller P. Creation of a molecular condensate by dynamically melting a Mott insulator. PHYSICAL REVIEW LETTERS 2002; 89:040402. [PMID: 12144471 DOI: 10.1103/physrevlett.89.040402] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2002] [Indexed: 05/23/2023]
Abstract
We propose the creation of a molecular Bose-Einstein condensate by loading an atomic condensate into an optical lattice and driving it into a Mott insulator with exactly two atoms per site. Molecules in a Mott insulator state are then created under well defined conditions by photoassociation with essentially unit efficiency. Finally, the Mott insulator is melted and a superfluid state of the molecules is created. We study the dynamics of this process and photoassociation of tightly trapped atoms.
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Affiliation(s)
- D Jaksch
- Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria
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938
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Kalosakas G, Rasmussen K KØ, Bishop AR. Delocalizing transition of Bose-Einstein condensates in optical lattices. PHYSICAL REVIEW LETTERS 2002; 89:030402. [PMID: 12144380 DOI: 10.1103/physrevlett.89.030402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2001] [Indexed: 05/23/2023]
Abstract
A Bose-Einstein condensate trapped in a two-dimensional optical lattice exhibits an abrupt transition manifested by the macroscopic wave function changing character from spatially localized to extended. Resulting from a bifurcation, this irreversible transition takes place as the interwell potential barrier is adiabatically decreased below a critical value. This is in sharp contrast to the corresponding one-dimensional case where such a bifurcation is absent and the extent of a localized mode is continuously tunable. We demonstrate how these phenomena can be experimentally explored.
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Affiliation(s)
- G Kalosakas
- Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 8754, USA
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939
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Vogels JM, Xu K, Ketterle W. Generation of macroscopic pair-correlated atomic beams by four-wave mixing in Bose-Einstein condensates. PHYSICAL REVIEW LETTERS 2002; 89:020401. [PMID: 12096987 DOI: 10.1103/physrevlett.89.020401] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2002] [Indexed: 05/23/2023]
Abstract
By colliding two Bose-Einstein condensates, we have observed strong bosonic stimulation of the elastic scattering process. When a weak input beam was applied as a seed, it was amplified by a factor of 20. This large gain atomic four-wave mixing resulted in the generation of two macroscopically occupied pair-correlated atomic beams.
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Affiliation(s)
- J M Vogels
- Department of Physics, MIT-Harvard Center for Ultracold Atoms, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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940
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Schlosser N, Reymond G, Grangier P. Collisional blockade in microscopic optical dipole traps. PHYSICAL REVIEW LETTERS 2002; 89:023005. [PMID: 12096994 DOI: 10.1103/physrevlett.89.023005] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2002] [Indexed: 05/23/2023]
Abstract
We analyze the operating regimes of a very small optical dipole trap, loaded from a magneto-optical trap, as a function of the atom loading rate, i.e., the number of atoms per second entering the dipole trap. We show that, when the dipole trap volume is small enough, a "collisional blockade" mechanism locks the average number of trapped atoms on the value 0.5 over a large range of loading rates. We also discuss the "weak loading" and "strong loading" regimes outside the blockade range, and we demonstrate experimentally the existence of these three regimes.
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Affiliation(s)
- N Schlosser
- Laboratoire Charles Fabry de l'Institut d'Optique, UMR 8501 du CNRS, 91403 Orsay, France
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941
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942
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André A, Duan LM, Lukin MD. Coherent atom interactions mediated by dark-state polaritons. PHYSICAL REVIEW LETTERS 2002; 88:243602. [PMID: 12059296 DOI: 10.1103/physrevlett.88.243602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2001] [Indexed: 05/23/2023]
Abstract
We suggest a technique to induce effective, controllable interactions between atoms that is based on Raman scattering into an optical mode propagating with a slow group velocity. The resulting excitation corresponds to the creation of spin-flipped atomic pairs in a way that is analogous to correlated photon emission in optical parametric amplification. The technique can be used for fast generation of entangled atomic ensembles, spin squeezing, and applications in quantum information processing.
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Affiliation(s)
- A André
- Physics Department, Harvard University, Cambridge, MA 02138, USA
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943
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Krämer M, Pitaevskii L, Stringari S. Macroscopic dynamics of a trapped Bose-Einstein condensate in the presence of 1D and 2D optical lattices. PHYSICAL REVIEW LETTERS 2002; 88:180404. [PMID: 12005672 DOI: 10.1103/physrevlett.88.180404] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2002] [Indexed: 05/23/2023]
Abstract
The hydrodynamic equations of superfluids for a weakly interacting Bose gas are generalized to include the effects of periodic optical potentials produced by stationary laser beams. The new equations are characterized by a renormalized interaction coupling constant and by an effective mass accounting for the inertia of the system along the laser direction. For large laser intensities the effective mass is directly related to the tunneling rate between two consecutive wells. The predictions for the frequencies of the collective modes of a condensate confined by a magnetic harmonic trap are discussed for both 1D and 2D optical lattices and compared with recent experimental data.
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Affiliation(s)
- M Krämer
- Dipartimento di Fisica, Università di Trento, Istituto Nazionale per la Fisica della Materia, I-38050 Povo, Italy
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944
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Góral K, Santos L, Lewenstein M. Quantum phases of dipolar bosons in optical lattices. PHYSICAL REVIEW LETTERS 2002; 88:170406. [PMID: 12005738 DOI: 10.1103/physrevlett.88.170406] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2001] [Indexed: 05/23/2023]
Abstract
The ground state of dipolar bosons placed in an optical lattice is analyzed. We show that the modification of experimentally accessible parameters can lead to the realization and control of different quantum phases, including superfluid, supersolid, Mott insulator, checkerboard, and collapse phases.
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Affiliation(s)
- K Góral
- Institut für Theoretische Physik, Universität Hannover, D-30167 Hannover, Germany
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945
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Demler E, Zhou F. Spinor bosonic atoms in optical lattices: symmetry breaking and fractionalization. PHYSICAL REVIEW LETTERS 2002; 88:163001. [PMID: 11955230 DOI: 10.1103/physrevlett.88.163001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2001] [Indexed: 05/23/2023]
Abstract
We study superfluid and Mott insulator phases of cold spin-1 Bose atoms with antiferromagnetic interactions in an optical lattice, including a usual polar condensate phase, a condensate of singlet pairs, a crystal spin nematic phase, and a spin singlet crystal phase. We suggest a possibility of exotic fractionalized phases of spinor Bose-Einstein condensates and discuss them in the language of Z2 lattice gauge theory.
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Affiliation(s)
- Eugene Demler
- Physics Department, Harvard University, Cambridge, Massachusetts 02138, USA
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946
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Dziarmaga J, Smerzi A, Zurek WH, Bishop AR. Dynamics of quantum phase transition in an array of Josephson junctions. PHYSICAL REVIEW LETTERS 2002; 88:167001. [PMID: 11955248 DOI: 10.1103/physrevlett.88.167001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2001] [Indexed: 05/23/2023]
Abstract
We study the dynamics of the Mott insulator-superfluid quantum phase transition in a periodic 1D array of Josephson junctions. We show that crossing the critical point at a finite rate with a quench time tau(Q) induces finite quantum fluctuations of the current around the loop proportional to tau(-1/6)(Q). This scaling could be experimentally verified with an array of weakly coupled Bose-Einstein condensates or superconducting grains.
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Affiliation(s)
- J Dziarmaga
- Los Alamos National Laboratory, Theory Division, Los Alamos, New Mexico 87545, USA
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947
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Abstract
Quantum information processors exploit the quantum features of superposition and entanglement for applications not possible in classical devices, offering the potential for significant improvements in the communication and processing of information. Experimental realization of large-scale quantum information processors remains a long-term vision, as the required nearly pure quantum behaviour is observed only in exotic hardware such as individual laser-cooled atoms and isolated photons. But recent theoretical and experimental advances suggest that cold atoms and individual photons may lead the way towards bigger and better quantum information processors, effectively building mesoscopic versions of 'Schrödinger's cat' from the bottom up.
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Affiliation(s)
- C Monroe
- FOCUS Center and Department of Physics, University of Michigan, Ann Arbor 48109-1120, USA.
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948
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Abstract
Coherent matter waves in the form of Bose-Einstein condensates have led to the development of nonlinear and quantum atom optics - the de Broglie wave analogues of nonlinear and quantum optics with light. In nonlinear atom optics, four-wave mixing of matter waves and mixing of combinations of light and matter waves have been observed; such progress culminated in the demonstration of phase-coherent matter-wave amplification. Solitons represent another active area in nonlinear atom optics: these non-dispersing propagating modes of the equation that governs Bose-Einstein condensates have been created experimentally, and observed subsequently to break up into vortices. Quantum atom optics is concerned with the statistical properties and correlations of matter-wave fields. A first step in this area is the measurement of reduced number fluctuations in a Bose-Einstein condensate partitioned into a series of optical potential wells.
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Affiliation(s)
- S L Rolston
- National Institute of Standards and Technology, Gaithersburg, MD 20899-8424, USA.
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949
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Abstract
This overview prefaces a collection of Insight review articles on the physics and applications of laser-cooled atoms. I will cast this work into a historical perspective in which laser cooling and trapping is seen as one of several research directions aimed at controlling the internal and external degrees of freedom of atoms and molecules.
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Affiliation(s)
- Steven Chu
- Physics Department, Stanford University, Stanford, California 94305-4060, USA
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950
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Abstract
The early experiments on Bose-Einstein condensation in dilute atomic gases accomplished three long-standing goals. First, cooling of neutral atoms into their motional ground state, thus subjecting them to ultimate control, limited only by Heisenberg's uncertainty relation. Second, creation of a coherent sample of atoms, in which all occupy the same quantum state, and the realization of atom lasers - devices that output coherent matter waves. And third, creation of a gaseous quantum fluid, with properties that are different from the quantum liquids helium-3 and helium-4. The field of Bose-Einstein condensation of atomic gases has continued to progress rapidly, driven by the combination of new experimental techniques and theoretical advances. The family of quantum-degenerate gases has grown, and now includes metastable and fermionic atoms. Condensates have become an ultralow-temperature laboratory for atom optics, collisional physics and many-body physics, encompassing phonons, superfluidity, quantized vortices, Josephson junctions and quantum phase transitions.
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Affiliation(s)
- James R Anglin
- Research Laboratory for Electronics, MIT-Harvard Center for Ultracold Atoms, and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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