Quantum metrological advantage of high-order squeezed states

TL;DR

This paper demonstrates that high-order non-Gaussian squeezed states can surpass standard Gaussian squeezed vacuum states in quantum metrology, offering significant advantages under certain conditions and robustness to some noise types.

Contribution

It introduces and analyzes the metrological benefits of high-order squeezing states, revealing their potential to outperform Gaussian states and discussing their robustness to decoherence.

Findings

High-order squeezing states provide significant metrological advantage over Gaussian states.

Advantage depends on the squeezing order and measurement observables.

Robustness varies with noise type, being more fragile under pure dephasing.

Abstract

Quantum correlations can be harnessed to improve the precision in parameter estimation beyond classical capabilities. Under a standard interferometric or rotation protocol, it is well established that the optimal single-mode Gaussian state is a standard squeezed vacuum, which enables Heisenberg limited precision. In this work, we investigate the potential metrological advantage of two distinct families involving high-order squeezing, namely, mth-phase and multisqueezed states. Our results show that these non-Gaussian states can grant a significant metrological advantage with respect to the optimal squeezed vacuum under equivalent conditions, i.e. at equal occupations. Their advantage holds both at low and large occupations, but its behavior critically depends on the chosen family of high-order squeezing. While higher squeezing orders enhance the advantage, this comes at the cost of higher-order observables in the measurement for full metrological performance. Finally, we study their robustness to standard decoherence channels, i.e. pure dephasing and zero-temperature damping. Employing standard squeezing as reference state, our results indicate a reasonable robustness against damping up to a certain noise strength, while their metrological advantage becomes fragile under pure dephasing. Our work shows the potential enhancement in quantum metrology beyond Gaussian states, carefully detailing the main challenges and limitations.