Monica Schleier-Smith
MIT
"A Squeezed Atomic Clock Enabled by Cavity Feedback"
ABSTRACT
Over a decade ago, the stability of atomic clocks reached the standard quantum limit, set by the projection noise inherent in measurements on an ensemble of uncorrelated particles. In a proof-of-principle experiment, we have now demonstrated a clock that surpasses this limit by operating with atoms in a particular type of entangled state called a "squeezed spin state". I will describe our method of preparing squeezed spin states, which harnesses the collective interaction of an atomic ensemble with the light field in an optical cavity. I will further present data characteristizing the squeezed clock, including the first measurement of an Allan deviation beyond the standard quantum limit.