Strongly Enhanced Spin Squeezing via Quantum Control

TL;DR

This paper introduces a novel quantum control method for significantly enhancing spin squeezing in atomic samples using a double-pass Faraday interaction and quantum eraser techniques, promising substantial improvements in quantum measurement precision.

Contribution

The paper presents a new approach combining double-pass Faraday interaction and quantum erasure to achieve exponential enhancement of spin squeezing, advancing quantum control methods.

Findings

Potential for ~10 dB of squeezing with current technology

Exponential squeezing enhancement through phase-matched interactions

Dependence of squeezing on decoherence and technical noise

Abstract

We describe a new approach to spin squeezing based on a double-pass Faraday interaction between an optical probe and an optically dense atomic sample. A quantum eraser is used to remove residual spin-probe entanglement, thereby realizing a single-axis twisting unitary map on the collective spin. This interaction can be phase-matched, resulting in exponential enhancement of squeezing. In practice the scaling and peak squeezing depends on decoherence, technical loss, and noise. A simplified model indicates ~10 dB of squeezing should be achievable with current laboratory parameters.