Persistent atomic spin squeezing at the Heisenberg limit

TL;DR

This paper proposes a practical scheme to achieve persistent spin squeezing at the Heisenberg limit by inhibiting further dynamics, making TACT more feasible in experiments.

Contribution

It introduces a simple method to stabilize spin squeezing at the TACT limit, overcoming experimental challenges and enabling persistent squeezing.

Findings

Scheme effectively freezes spin squeezing at optimal points

Protocols relax experimental constraints for TACT realization

Achieves persistent spin squeezing at the Heisenberg limit

Abstract

Two well-known mechanisms, one-axis twisting (OAT) and two-axis countertwisting (TACT), generate spinsqueezed states dynamically. The latter provides better spin squeezing (SS) but has not been demonstrated as the form of its interaction does not occur naturally in known physical systems. Several proposals for realizing effective TACT transformed from OAT require stringent experimental conditions in order to overcome the resulting nonstationary (oscillating) SS and continuously varying mean spin directions. This work presents a simple scheme that solves both problems by freezing SS at an optimal point and realizing effectively persistent SS by inhibiting further squeezing dynamics. Explicit procedures are outlined for persistent SS of the TACT limit. Protocols based on our scheme favorably relax experimental demands, which significantly brighten the prospects for realizing TACT.