Robust Spin Squeezing Preservation in Photonic Crystal Cavities

TL;DR

This paper demonstrates how to preserve spin squeezing in atomic ensembles within photonic crystal cavities by detuning modifications, highlighting the role of bound states and differences between isotropic and anisotropic cases for quantum metrology.

Contribution

It introduces a method for robust spin squeezing preservation using detuning in photonic crystal cavities, emphasizing the impact of bound states and cavity anisotropy.

Findings

Bound states determine spin squeezing preservation.

Steady-state spin squeezing behavior differs between isotropic and anisotropic cavities.

A sudden transition in squeezing occurs in anisotropic cavities as atomic frequency crosses the band edge.

Abstract

We show that the robust spin squeezing preservation can be achieved by utilizing detuning modification for an ensemble of N separate two-level atoms embedded in photonic crystal cavities (PCC). In particular, we explore the different dynamical behaviors of spin squeezing between isotropic and anisotropic PCC cases when the atomic frequency is inside the band gap. In both cases, it is shown that the robust preservation of spin squeezing is completely determined by the formation of bound states. Intriguingly, we find that unlike the isotropic case where steady-state spin squeezing varies smoothly when the atomic frequency moves from the inside to the outside band edge, a sudden transition occurs for the anisotropic case. The present results may be of direct importance for, e.g., quantum metrology in open quantum systems.