Atom-pair tunneling and quantum phase transition in an asymmetry double-well trap in the strong-interaction regime

Abstract

In this paper, the quantum effect of nonlinear co-tunnelling process, depended on atom-pair tunneling and asymmetry of an double-well trap, is studied in an asymmetrical extended Bose-Hubbard model. Due to existing of atom-pair tunneling, describing quantum phenomena of ultracold atom-gas clouds in an asymmetrical double-well trap, the asymmetrical extended Bose-Hubbard model is better than the previous Bose-Hubbard model model by comparing with the experiment data in reference[1] . It is analytical investigated that dynamics and quantum phase transition depended on atom-pair tunneling and asymmetry. Importantly, it shows that the asymmetry of the extended Bose-Hubbard model, corresponding to the bias between double wells, leads to a number of resonance tunneling processes which is renamed as conditional resonance tunneling, and corrects the atom-number parity effect by controlling the bias between double wells.