Revisiting the impact of dissipation on time-reversed one-axis-twist quantum-sensing protocols

TL;DR

This paper systematically analyzes how dissipation affects different implementations of time-reversed one-axis-twist spin-squeezing protocols for quantum sensing, revealing varying robustness and sensitivities to noise.

Contribution

It provides a comprehensive comparison of three OAT-based sensing schemes under dissipation, highlighting their distinct resilience and the increased sensitivity of symmetric cavity feedback to noise.

Findings

Different implementations show markedly different dissipation resilience.

Symmetric cavity feedback is more sensitive to dissipation than previously thought.

Dissipation impacts the metrological gain variably across schemes.

Abstract

Spin squeezing can increase the sensitivity of interferometric measurements of small signals in large spin ensembles beyond the standard quantum limit. In many practical settings, the ideal metrological gain is limited by imperfect readout of the sensor. To overcome this issue, protocols based on time reversal of unitary one-axis-twist (OAT) spin-squeezing dynamics have been proposed. Such protocols mitigate readout noise and, when implemented using cavity feedback, have been argued to also be robust against dissipation as long as the collective cooperativity of the system is sufficiently large [Davis et al., PRL 116, 053601 (2016)]. Here, we perform a careful systematic study of dissipative effects on three different implementations of a OAT twist-untwist sensing scheme (based on symmetric as well as asymmetric cavity feedback and on a Tavis-Cummings interaction). Our full treatment shows that the three approaches have markedly different properties and resilience when subject to dissipation. Moreover, the metrological gain for an implementation using symmetric cavity feedback is more sensitive to undesired dissipation than was previously appreciated.