Experimental quantum-enhanced response function estimation

TL;DR

This paper demonstrates experimentally that quantum-enhanced methods improve the estimation of a system's response function, outperforming classical approaches by effectively combining quantum resources with interpolation techniques.

Contribution

The work provides the first experimental demonstration of quantum resources improving continuous function estimation, specifically in phase response measurement of a liquid crystal.

Findings

Quantum phase estimation outperforms classical methods in response function reconstruction.

Quantum resources reduce statistical error in fiducial point evaluation.

The approach highlights the importance of balancing statistical and interpolation errors.

Abstract

Characterizing a system often demands learning its response function to an applied field. Such knowledge is rooted on the experimental evaluation of punctual fiducial response and interpolation to access prediction at arbitrary values. Quantum metrological resources are known to provide enhancement in assessing these fiducial points, but the implications for improved function estimation have only recently been explored, and have not been yet demonstrated. Here we show an experimental realization of function estimation based on a photonic achitecture. The phase response of a liquid-crystal to a voltage has been reconstructed by means of quantum and classical phase estimation, providing evidence of the superiority of the former and highlighting the interplay between punctual statistical error and interpolation error. Our results show how quantum resources should successfully be employed to access the rich information contained in continuous signals.