Quantum coherence for Bose-Einstein condensates induced by an imaginary potential

Abstract

The single-body Schr\"odinger equation with complex potentials has been studied intensively. In this work, we investigate the dynamical process for Bose-Einstein condensed gases, based on the many-body Schr\"odinger equation with complex potentials. It is shown that a weakly imaginary periodic potential may induce perfect quantum coherence between different condensates, even without considering interatomic interactions. This imaginary-potential-induced quantum coherence may be tested with present experimental techniques. We also consider the quantum coherence in the presence of both the imaginary periodic potential and interatomic interactions.