Specular mirrors in atom interferometers
Effects based on quantum clock interference rely on atom interferometers with a non-vanishing proper time difference. We propose an atom interferometer consisting of two beam splitters to separate and recombine the two branches of the interferometer, and two specular mirrors in the middle that invert the incoming momentum. We show that with the help of specular reflection the difference in proper time between the two branches of the resulting geometry is non-vanishing, in contrast to the familiar Mach-Zehnder interferometer with mirrors that rely on a diffractive mechanism. Finally, we propose a realization of specular mirrors by strongly detuned evanescent light fields.