Quench dynamics and atom number parity effect of bosonic condensates in a double-well potential

Abstract

We investigate the dynamical evolution and atom number parity effect of bosonic condensates in a double-well potential within the two-mode Bose-Hubbard model (BHM), following a quench from the Josephson to the Fock regime. We demonstrate the different behaviors of systems with even and odd numbers of atoms on a mesoscopic scale by calculating the correlation function ( )  t , visibility α, number fluctuation  and entanglement entropy S. In contrast to the full collapse and revival of quantum correlations for systems with even numbers of atoms, we find that the correlations for systems with odd numbers will not collapse thoroughly, predicting a nonvanishing interference pattern. We relate this phenomenon to the parity effect of the energy spectrum, explain the effect in the pseudo-angular-momentum representation of the BHM Hamiltonian and suggest its confirmation in experiments.