Achieving Heisenberg-limited metrology with spin cat states via interaction-based readout

TL;DR

This paper demonstrates that spin cat states can achieve Heisenberg-limited measurement precision using an interaction-based readout scheme, which is robust and feasible with current experimental techniques.

Contribution

The authors propose a novel interaction-based readout method for spin cat states that saturates their ultimate precision bounds and is more robust against detection noise.

Findings

Spin cat states can reach Heisenberg-limited precision.

Interaction-based readout saturates the ultimate measurement bounds.

Scheme is robust against detection noise and experimentally feasible.

Abstract

Spin cat states are promising candidates for quantum-enhanced measurement. Here, we analytically show that the ultimate measurement precision of spin cat states approaches the Heisenberg limit, where the uncertainty is inversely proportional to the total particle number. In order to fully exploit their metrological ability, we propose to use the interaction-based readout for implementing phase estimation. It is demonstrated that the interaction-based readout enables spin cat states to saturate their ultimate precision bounds. The interaction-based readout comprises a one-axis twisting, two $\frac{\pi}{2}$ pulses, and a population measurement, which can be realized via current experimental techniques. Compared with the twisting echo scheme on spin squeezed states, our scheme with spin cat states is more robust against detection noise. Our scheme may pave an experimentally feasible way to achieve Heisenberg-limited metrology with non-Gaussian entangled states.