Bragg spectroscopic interferometer and quantum measurement-induced correlations in atomic Bose-Einstein condensates

Abstract

We theoretically analyse the Bragg spectroscopic interferometer of two spatially separated atomic Bose-Einstein condensates that was experimentally realized by Saba et al (2005 Science 307 1945) by continuously monitoring the relative phase evolution. Even though atoms in the lightstimulated Bragg scattering interact with intense coherent laser beams, we show that the phase is created by quantum measurement-induced backaction on the homodyne photocurrent of the lasers, opening the possibilities for quantumenhanced interferometric schemes. We identify two regimes of phase evolution: a running phase regime observed in the experiment of Saba et al, which is sensitive to an energy offset and suitable for an interferometer, and a trapped phase regime, which can be insensitive to the applied forces and detrimental to interferometric applications. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.