Enhancing optical clocks with ultrastable lasers and spin-squeezing

Details
Speaker Name/Affiliation
John Michael Robinson / Ye Group
When
-
Seminar Type
Location (Room)
JILA Auditorium
Event Details & Abstracts

Abstract:

 

Traditional optical atomic clocks are limited in their performance by laser frequency noise and the intrinsic quantum noise of uncorrelated atoms. In this thesis, we advance the field of optical clocks on both of these fronts. By developing the next generation of ultrastable laser technology, we enable clock comparisons that have approached the quantum projection noise limit. To go beyond this limit, we build and operate an optical clock with the capability of spin-squeezing. Employing conditional spin squeezing via quantum nondemolition measurements based on cavity QED, we produce a spin squeezed state that yields a spectroscopic enhancement of 1.8 dB beyond the standard quantum limit. We then run a clock comparison between two spin squeezed clock ensembles, making use of a movable optical lattice to individually squeeze and readout the ensembles with cavity QED. This differential comparison between the two squeezed clocks directly verifies enhanced clock stability of 2.0 dB beyond the quantum projection noise limit. This constitutes the first direct demonstration of quantum enhanced measurement in an operational optical atomic clock.