Wave function recombination instability in cold atom interferometers

TL;DR

This paper analyzes a wave function recombination instability in cold atom interferometers caused by weak nonlinearity, leading to exponential amplification of modes near specific phase differences, affecting both trapped and beam configurations.

Contribution

It provides a theoretical analysis of the wave function recombination instability in cold atom interferometers due to condensate nonlinearity, highlighting conditions for its occurrence.

Findings

Instability occurs near phase differences of odd multiples of PI.

Weak nonlinearity leads to exponential mode amplification.

Both trapped-atom and beam interferometers are affected.

Abstract

Cold atom interferometers use guiding potentials that split the wave function of the Bose-Einstein condensate and then recombine it. We present theoretical analysis of the wave function recombination instability that is due to the weak nonlinearity of the condensate. It is most pronounced when the accumulated phase difference between the arms of the interferometer is close to an odd multiple of PI and consists in exponential amplification of the weak ground state mode by the strong first excited mode. The instability exists for both trapped-atom and beam interferometers.