By making use of the invariant theory,the exact solution for a time-dependent system of double-well Bose-Einstein Condensate and corresponding geometric phase are obtained.;
We describe the behavior of two coupled Bose-Einstein condensates in time-dependent (TD) trap potentials and TD Rabi (or tunneling) frequency using the two-mode approach. Starting from Bloch states, we succeed in obtaining analytical solutions for the TD Schr\"odinger equation and present a detailed analysis of the relative and geometric phases acquired by the wave function of the condensates, as well as their population imbalance. We also establish a connection between the geometric phases and constants of motion which characterize the dynamic of the system. Besides analyzing the affects of temporality on condensates that differ by hyperfine degrees of freedom (internal Josephson effect), we also do present a brief discussion of a one-species condensate in a double-well potential (external Josephson effect).
The perturbative evaluation of the time-dependent quantum transport is investigated by making use of the Lewis-Riesenfeld invariant theory and the invariant-related unitary transformation formulation in this paper.We obtain the complete set of solutions of the time-dependent Schrdinger equation governing the behaviour of electrons in a double-well structure. Based on these exact solutions,we obtain the first-order quantum rate equation by regarding the interaction Hamiltonian between the double-well structures and the heat reservoirs as the perturbative Hamiltonian.An approach to the geometric phase factor (Berry's phase factor) in the adiabatic quantum transport process is briefly discussed in this paper.We hold that the formulation presented here has advantages in dealing with transport problem over the method proposed by Gurvitz et al.