481 research outputs found
Probing the light induced dipole-dipole interaction in momentum space
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
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
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
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
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
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
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
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
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.
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