Squeezing giant spin states via geometric phase control in cavity-assisted Raman transitions

TL;DR

This paper proposes a practical method to generate spin squeezing in large ensembles using geometric phase control via cavity-assisted Raman transitions, enhancing quantum metrology sensitivity.

Contribution

It introduces a novel protocol leveraging cavity-assisted Raman transitions to achieve significant spin squeezing through geometric phase control.

Findings

Achieves considerable spin squeezing at specific evolution times.

Potential to improve quantum metrology sensitivity by about two orders.

Realizes an effective Dicke model in a double Lambda system.

Abstract

Squeezing ensemble of spins provides a way to surpass the standard quantum limit (SQL) in quantum metrology and test the fundamental physics as well, and therefore attracts broad interest. Here we propose an experimentally accessible protocol to squeeze a giant ensemble of spins via the geometric phase control. Using the cavity-assisted Raman transitions in a double $\Lambda$-type system, we realize an effective Dicke model. Under the condition of vanishing effective spin transition frequency, we find a particular evolution time where the cavity decouples from the spins and the spin ensemble is squeezed considerably. Our scheme has the potential to improve the sensitivity in quantum metrology with spins by about two orders.