Quantum-limited estimation of continuous spontaneous localization

TL;DR

This paper employs quantum estimation theory to evaluate the potential of optomechanical and spin-assisted systems for detecting the strength of collapse mechanisms in continuous spontaneous localization models.

Contribution

It introduces a quantum estimation framework for CSL parameters using optomechanical and spin-assisted setups, comparing measurement strategies for the first time.

Findings

Optical measurements like homodyne and heterodyne are effective for CSL estimation.

Spin-assisted systems offer alternative measurement strategies with comparable performance.

The study quantifies the sensitivity limits for detecting CSL effects in different quantum systems.

Abstract

We apply the formalism of quantum estimation theory to extract information about potential collapse mechanisms of the continuous spontaneous localisation (CSL) form. In order to estimate the strength with which the field responsible for the CSL mechanism couples to massive systems, we consider the optomechanical interaction between a mechanical resonator and a cavity field. Our estimation strategy passes through the probing of either the state of the oscillator or that of the electromagnetic field that drives its motion. In particular, we concentrate on all-optical measurements, such as homodyne and heterodyne measurements. We also compare the performances of such strategies with those of a spin-assisted optomechanical system, where the estimation of the CSL parameter is performed through time-gated spin-like measurements.