Quantum-enhanced differential atom interferometers and clocks with spin-squeezing swapping

Abstract

Thanks to common-mode noise rejection, differential configurations are crucial for realistic applications of phase and frequency estimation with atom interferometers. Currently, differential protocols with uncorrelated particles and mode-separable settings reach a sensitivity bounded by the standard quantum limit (SQL). Here we show that differential interferometry can be understood as a distributed multiparameter estimation problem and can benefit from both mode and particle entanglement. Our protocol uses a single spin-squeezed state that is mode-swapped among common interferometric modes. The mode swapping is optimized to estimate the differential phase shift with sub-SQL sensitivity. Numerical calculations are supported by analytical approximations that guide the optimization of the protocol. The scheme is also tested with simulation of noise in atomic clocks and interferometers.

Collectively enhanced Ramsey readout by cavity sub- to superradiant transition

“…Quantum sensors such as atomic clocks, with their unprecedented accuracy and stability 1 – 6 , have revolutionized fields ranging from fundamental physics to global positioning systems. The development of novel state detection methods plays a pivotal role in improving the performance and capabilities of these atomic sensors 7 – 12 . In recent years, quantum technologies have emerged as a promising avenue for enhancing sensitivities in measurement and sensing applications.…”