Atom-pair tunnelling-induced quantum phase transition and scaling behaviour of fidelity susceptibility in the extended boson Josephson-junction model

作者：Liu J L^*; Liang J Q

来源：Journal of Physics B: Atomic, Molecular and Optical Physics , 2011, 44(2): 025101.

DOI：10.1088/0953-4075/44/2/025101

In this paper we theoretically investigate the nonlinear tunnelling of two weakly linked Bose-Einstein condensates in a double-well trap in a strong interaction regime with the two-body interaction extended to neighbouring lattice sites. As a consequence the boson Josephson-junction tunnelling depends on the atom-atom interaction and the total atom number as well. A crucial atom-pair tunnelling term, obtained directly from the extension, results in significant energy spectrum corrections and an abrupt change of the ground state viewed as quantum phase transition. An atom-number oscillation state with a tunable relative phase between two Bose-Einstein condensates predicted for the first time is seen to be a degenerate ground state in an interaction region. The quantum phase transitions between degenerate and non-degenerate ground states driven by the atom-pair tunnelling are analysed. We show the scaling behaviours and the critical exponents of fidelity susceptibility, which can classify the universality.

• 出版日期2011-1-28
• 单位山西大学