Scaling laws for the sensitivity enhancement of non-Gaussian spin states

TL;DR

This paper analyzes how the quantum metrological advantage of over-squeezed non-Gaussian spin states scales with system size and preparation time, considering decoherence effects, and offers practical guidelines for experimental implementation.

Contribution

It provides the first detailed large-N scaling laws for quantum gain in non-Gaussian spin states and explores the impact of decoherence, guiding optimal experimental strategies.

Findings

Quantum gain scales with system size and preparation time.

Decoherence causes a discontinuous change in quantum advantage.

Analytical formulas enable practical implementation in experiments.

Abstract

We identify the large-$N$ scaling of the metrological quantum gain offered by over-squeezed spin states that are accessible by one-axis-twisting, as a function of the preparation time. We further determine how the scaling is modified by relevant decoherence processes and predict a discontinuous change of the quantum gain at a critical preparation time that depends on the noise. Our analytical results provide recipes for optimal and feasible implementations of quantum enhancements with non-Gaussian spin states in existing experiments, well beyond the reach of spin squeezing.