We analyze theoretically an optical scheme to detect the phase of a Bose-Einstein condensate associated with spontaneously broken gauge symmetry. Two condensates in different Zeeman states are confined to the same trap, and two phase-coherent laser beams are used to drive Raman transitions between the condensates. Amplification of one of the Raman beams immediately following the turn-on of light is an unambiguous sign of the presence of phase coherence in the atoms. © 1996 The American Physical Society.

• Received 8 May 1996

DOI:https://doi.org/10.1103/PhysRevA.54.R4629