https://doi.org/10.1140/epjd/e2012-20682-7
Regular Article
Quantum phase transition and dynamics induced by atom-pair tunnelling of Bose-Einstein condensates in a double-well potential
1 School of Physics, Beijing Institute of Technology, Beijing 100081, P.R. China
2 National Laboratory of Science and Technology on Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100088, P.R. China
3 HEDPS, Center for Applied Physics and Technology, Peking University, Beijing 100084, P.R. China
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e-mail: lbfu@iapcm.ac.cn
Received: 28 November 2011
Received in final form: 23 February 2012
Published online: 19 April 2012
We investigate the quantum phase transition (QPT) and dynamics induced by atom-pair tunnelling of Bose-Einstein condensates in a symmetric double well under the mean-field approximation. We find the system undergoes a new QPT towards phase-locking state when atom-pair tunnelling is strong enough, and the critical point of self-trapping QPT is shifted by atom-pair tunnelling. As for the dynamics, the system displays localized dynamical behaviour: phase-locking motion and self-trapping motion. We further study the correlation between this localized dynamics and QPT, and find that the area of the localized trajectories in the phase space can serve as an order parameter for both QPTs. The critical exponent of this order parameter is also discussed.
Key words: Cold Matter and Quantum Gas
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2012
