Phase coherence in a driven double-well system

The dynamics of a molecular field incoherently pumped by the photoassociation of fermionic atoms and coupled by quantum tunneling in a double-well potential was analyzed. The relative phase distribution of the molecular modes in each well and their phase coherence was observed to be building up owing to quantum-mechanical fluctuations starting from the vacuum state. Three qualitatively different steady-state phase distributions, were identified depending on the ratio of the molecule-molecule interaction strength to interwell tunneling. The crossover from a phase-coherent regime to a phase-incoherent regime was examined as the ratio of the molecule-molecule interaction strength to interwell tunneling increased.