arXiv:1009.3666 · Physical Review A

Time-dependent self-trapping of Bose-Einstein condensates in a double-well potential

B. Cui, L. C. Wang, X. X. Yi

Published Dec 7, 2010• 24 citations

Abstract

Based on the mean-field approximation and a phase-space analysis, we discuss the dynamics of Bose-Einstein condensates (BECs) in a double-well potential. The condensates are found to be trapped in the time-dependent eigenstates of the effective Hamiltonian; we refer to this effect as time-dependent self-trapping of BECs. By comparison of this self-trapping with the adiabatic evolution, we find that adiabatic evolution beyond the traditional adiabatic condition can be achieved in BECs. Furthermore, the population imbalance of the BECs in the wells can be controlled by manipulating the atom-atom couplings and the driving field. The fixed points for the system are also calculated and discussed.

DOI: 10.1103/physreva.82.062105

Related papers

A heuristic approach to BEC self-trapping in double wells beyond the mean field

K Rapedius

We present a technically simple treatment of self-trapping of Bose-Einstein condensates in double well traps based on intuitive semi-classical approximations. Our analysis finally leads to a convenient closed form approximation for the time-averaged population imbalance valid in both the mean-field case and in the case of finite particle numbers for short times.

arXiv:1112.4721Journal of Physics B Atomic Molecular and Optical PhysicsMar 26, 20124 citations

Adiabatic splitting, transport, and self-trapping of a Bose-Einstein condensate in a double-well potential

Carlo Ottaviani, V. Ahufinger, R. Corbalán +1 more

We show that the adiabatic dynamics of a Bose-Einstein condensate (BEC) in a double-well potential can be described in terms of a dark variable resulting from the combination of the population imbalance and the spatial atomic coherence between the two wells. By means of this dark variable, we extend, to the nonlinear matter-wave case, the recent proposal by Vitanov and Shore [Phys. Rev. A 73, 053402 (2006)] on adiabatic passage techniques to coherently control the population of two internal levels of an atom or molecule. We investigate the conditions to adiabatically split or transport a BEC as well as to prepare an adiabatic self-trapping state by the optimal delayed temporal variation of the tunneling rate via either the energy bias between the two wells or the BEC nonlinearity. The emergence of nonlinear eigenstates and unstable stationary solutions of the system as well as their role in the breaking down of the adiabatic dynamics is investigated in detail.

arXiv:0906.3976Physical Review AApr 19, 201037 citations

Adiabatic splitting and self-trapping of a Bose-Einstein condensate in a double-well potential

Carlo Ottaviani, V. Ahufinger, R. Corbalán +1 more

Bose Einstein condensates (BECs) in double well potentials have drawn a lot of attention for the possibilities they offer to study fundamental quantum mechanical effects at the macroscopic level as well as for potential applications like interferometry, high precision measurements or thermometry. In contrast to Josephson junctions realized in superconductors and superfluids, in BEC the interatomic interactions play a crucial role leading to anharmonic Josephson oscillations, if the initial population imbalance of the two wells is below a critical value, and to macroscopic quantum self-trapping i.e, inhibition of large amplitude Josephson oscillations above the threshold for the population imbalance. In this paper, a novel technique to adiabatically control of BEC in a double-well potential is proposed. The adiabatic dynamics of a BEC in a double well potential can be described in terms of a dark variable resulting from a combination of the population imbalance and the spatial atomic coherence.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)Jun 1, 20090 citations

Self-trapping and its periodic modulation of Bose-Einstein condensates in double-well trap

Guanfang Wang, Fu Li-Bin, Zhao Hong +2 more

Self-trapping of Bose-Einstein condensates (BEC) in double-well trap is investigated. Two kinds of self-trapping are discussed through phase space analysis in the mean-field approximation: 1) The number of atoms oscillates near an equilibrium point in the phase space, while relative phase increases monotonously with time (running-phase); 2) Both the number of particles and the relative phase oscillate near an equilibrium point in the phase space. In particular, we investigate how an external periodic filed influence the self-trapping. It is found that the external periodic field may dramatically modulate the critical points at which the transition to self-trapping occurs. With this, we can observe self-trapping phenomenon in a dilute Bose-Einstein condensate with a very weak interaction as well. Finally, the effect of many-body quantum fluctuation on self-trapping is also studied. We also discuss how to observe the self-trapping phenomenon with present experimental techniques.

Acta Physica SinicaJan 1, 200529 citations

Strong-coupling dynamics of Bose–Einstein condensate in a double-well trap

Valentin O. Nesterenko, A N Novikov, E. Suraud

Dynamics of the repulsive Bose–Einstein condensate (BEC) in a double-well trap is explored within the 3D time-dependent Gross–Pitaevskii equation. The model avoids numerous common approximations (two-mode treatment, time-space factorization, fixed values of the chemical potential and barrier penetrability, etc) and thus may provide a realistic description of BEC dynamics, including both weak-coupling (sub-barrier) and strong-coupling (above-barrier) regimes and their crossover. The strong coupling regime is achieved by increasing the number N of BEC atoms and thus the chemical potential. The evolution with N of Josephson oscillations (JO) and macroscopic quantum self-trapping (MQST) is examined and the crucial impact of the BEC interaction is demonstrated. At weak coupling, the calculations well reproduce the JO/MQST experimental data. At strong coupling with a significant overlap of the left and right BECs, we observe a remarkable persistence of the Josephson-like dynamics: the JO and MQST converge to a high-frequency JO-like mode where both population imbalance and phase difference oscillate around the zero averages.

arXiv:1205.3687Journal of Physics B Atomic Molecular and Optical PhysicsOct 24, 20125 citations

The self-trapping of superfluid Fermi gases in the Bose-Einstein condensation regime and in unitarity

Wen-Yuan Wang, Yang Yang, Hongjuan Meng +4 more

In the mean-field theory and two-mode approximation, we study the self-trapping of superfluid Fermi gases in the BEC regime and in unitarity by observing the evolution of the population imbalance with time and the variation of the average of population imbalance with several non-linear interaction parameters. The high-frequency modulations of both the symmetric double-well potential and the potential well are studied. The boundary conditions of the self-trapping and non-self-trapping are given. We find that high-frequency modulation in a certain range of modulation can make the self-trapping phenomenon easier to achieve. Finally, we study the influence of the initial value on self-trapping, and find that the increase of the absolute of the initial value can make the self-trapping more conducive to the realization.

Acta Physica SinicaJan 1, 20121 citation