Quantum effects of an atomic Bose–Einstein condensate interacting with a laser field in a double-well potential

Abstract

We have investigated quantum effects of an atomic Bose–Einstein condensate in a double-well potential interacting with a single-mode quantum traveling-wave laser field. It is predicted that when the atom–field system is initially in even (odd) coherent states, atoms in the two wells can be in a self-trapping state when the tunneling frequency satisfies two specific values in which the resonant and far off-resonant cases are included. In addition, there exists an alternating current with the sinusoidal oscillations between the two wells, but no dc atomic tunneling current. The influences of the laser field on the oscillatory frequencies of the population difference and the atomic tunneling current are discussed in detail. Expressions for the energy exchange between atoms and photons are also given. As a possible application, by measurement of the atomic tunneling current between the two wells, the number of Bose condensed atoms can be evaluated.