486 research outputs found

    Probing the light induced dipole-dipole interaction in momentum space

    Full text link
    We theoretically investigate the mechanical effect of the light-induced dipole-dipole interaction potential on the atoms in a Bose-Einstein condensate. We present numerical calculations on the magnitude and shape of the induced potentials for different experimentally accessible geometries. It is shown that the mechanical effect can be distinguished from the effect of incoherent scattering for an experimentally feasible setting

    Synchronized and desynchronized phases of coupled non-equilibrium exciton-polariton condensates

    Full text link
    We theoretically analyze the synchronized and desynchronized phases of coupled non-equilibrium polariton condensates within mean field theory. An analytical condition for the existence of a synchronized phase is derived for two coupled wells. The case of many wells in a 2D disordered geometry is studied numerically. The relation to recent experiments on polariton condensation in CdTe microcavities is discussed.Comment: 5 pages, 3 figure

    The role of inter-well tunneling strength on coherence dynamics of two-species Bose-Einstein condensates

    Full text link
    Coherence dynamics of two-species Bose-Einstein condensates in double wells is investigated in mean field approximation. We show that the system can exhibit decoherence phenomena even without the condensate-environment coupling and the variation tendency of the degree of coherence depends on not only the parameters of the system but also the initial states. We also investigate the time evolution of the degree of coherence for a Rosen-Zener form of tunneling strength, and propose a method to get a condensate system with certain degree of coherence through a time-dependent tunneling strength

    Control of unstable macroscopic oscillations in the dynamics of three coupled Bose condensates

    Get PDF
    We study the dynamical stability of the macroscopic quantum oscillations characterizing a system of three coupled Bose-Einstein condensates arranged into an open-chain geometry. The boson interaction, the hopping amplitude and the central-well relative depth are regarded as adjustable parameters. After deriving the stability diagrams of the system, we identify three mechanisms to realize the transition from an unstable to stable behavior and analyze specific configurations that, by suitably tuning the model parameters, give rise to macroscopic effects which are expected to be accessible to experimental observation. Also, we pinpoint a system regime that realizes a Josephson-junction-like effect. In this regime the system configuration do not depend on the model interaction parameters, and the population oscillation amplitude is related to the condensate-phase difference. This fact makes possible estimating the latter quantity, since the measure of the oscillating amplitudes is experimentally accessible.Comment: 25 pages, 12 figure

    Optical realization of the two-site Bose-Hubbard model in waveguide lattices

    Full text link
    A classical realization of the two-site Bose-Hubbard Hamiltonian, based on light transport in engineered optical waveguide lattices, is theoretically proposed. The optical lattice enables a direct visualization of the Bose-Hubbard dynamics in Fock space.Comment: to be published, J Phys. B (Fast Track Communication

    The Meaning of Life Wayang Wong Sriwedari Players

    Full text link
    The meaning of life is something that is considered important, valuable, and desirable as well as provide special value to one's self. The meaning of life is also worthy life goals. This study aims to find a vision of the meaning of life from the players who are in the wayang wong Sriwedari in Surakarta. This study used a qualitative method using a phenomenological approach. The number of subjects in the study were four people determined purposively. The results obtained from this study is the background in the selection of the fourth subject wayang wong job as a player because it has the talent and have ancestors who are involved in the arts wayang wong. Reason subjects persist in work because they love their work, do not have any other skills, and the desire to work. They also have the same goal in the work is provide for his family. Fourth research subject grateful for what they have earned, and considers his life prosperous. Physical changes to give effect to the subject in the work, other than that obtained in any role the show has been changed into buto figures and waistband. Achievement of the meaning of life is obtained subject of happiness, work wholeheartedly, loving family, successful children, produce works of art, to support my wife and kids, and the third male subjects have in common is their role as a father. Their efforts in achieving the meaning of life is done through the value of work, and the value being the value appreciation

    Nonlinear Self-Trapping of Matter Waves in Periodic Potentials

    Full text link
    We report the first experimental observation of nonlinear self-trapping of Bose-condensed 87Rb atoms in a one dimensional waveguide with a superimposed deep periodic potential . The trapping effect is confirmed directly by imaging the atomic spatial distribution. Increasing the nonlinearity we move the system from the diffusive regime, characterized by an expansion of the condensate, to the nonlinearity dominated self-trapping regime, where the initial expansion stops and the width remains finite. The data are in quantitative agreement with the solutions of the corresponding discrete nonlinear equation. Our results reveal that the effect of nonlinear self-trapping is of local nature, and is closely related to the macroscopic self-trapping phenomenon already predicted for double-well systems.Comment: 5 pages, 4 figure

    Quantum Bose Josephson Junction with binary mixtures of BECs

    Full text link
    We study the quantum behaviour of a binary mixture of Bose-Einstein condensates (BEC) in a double-well potential starting from a two-mode Bose-Hubbard Hamiltonian. We focus on the small tunneling amplitude regime and apply perturbation theory up to second order. Analytical expressions for the energy eigenvalues and eigenstates are obtained. Then the quantum evolution of the number difference of bosons between the two potential wells is fully investigated for two different initial conditions: completely localized states and coherent spin states. In the first case both the short and the long time dynamics is studied and a rich behaviour is found, ranging from small amplitude oscillations and collapses and revivals to coherent tunneling. In the second case the short-time scale evolution of number difference is determined and a more irregular dynamics is evidenced. Finally, the formation of Schroedinger cat states is considered and shown to affect the momentum distribution.Comment: 14 pages, 4 figure

    Quantum dynamics of a binary mixture of BECs in a double well potential: an Holstein-Primakoff approach

    Get PDF
    We study the quantum dynamics of a binary mixture of Bose-Einstein condensates (BEC) in a double-well potential starting from a two-mode Bose-Hubbard Hamiltonian. Focussing on the regime where the number of atoms is very large, a mapping onto a SU(2) spin problem together with a Holstein-Primakoff transformation is performed. The quantum evolution of the number difference of bosons between the two wells is investigated for different initial conditions, which range from the case of a small imbalance between the two wells to a coherent spin state. The results show an instability towards a phase-separation above a critical positive value of the interspecies interaction while the system evolves towards a coherent tunneling regime for negative interspecies interactions. A comparison with a semiclassical approach is discussed together with some implications on the experimental realization of phase separation with cold atoms.Comment: 12 pages, 7 figures, accepted for publication in J. Phys.
    • …