A Wigner Function Approach to Coherence in a Talbot-Lau Interferometer

TLDR: In this article, the authors model the signal of a trapped interferometer using two short laser pulses, separated by time T, which act as a phase grating for the matter waves.

Abstract: Using a thermal gas, we model the signal of a trapped interferometer. This interferometer uses two short laser pulses, separated by time T, which act as a phase grating for the matter waves. Near time 2 T , there is an echo in the cloud’s density due to the Talbot-Lau effect. Our model uses the Wigner function approach and includes a weak residual harmonic trap. The analysis shows that the residual potential limits the interferometer’s visibility, shifts the echo time of the interferometer, and alters its time dependence. Loss of visibility can be mitigated by optimizing the initial trap frequency just before the interferometer cycle begins.