A measurement-based protocol for the generation of delocalised quantum states of a mechanical system

TL;DR

This paper introduces a measurement-based protocol to generate nonclassical, delocalized quantum states of a mechanical oscillator in cavity optomechanics, enabling advances in quantum sensing and macroscopic quantum tests.

Contribution

It presents a novel heralding protocol using optical detection to produce non-Gaussian mechanical states, with analysis of different schemes and realistic experimental conditions.

Findings

Heralding rates are quantified for different schemes.

Mechanical Wigner function negativity can be achieved under certain conditions.

The protocol is robust to finite temperature and detection inefficiencies.

Abstract

Non-Gaussian mechanical states are a key resource for quantum-enhanced sensing and tests of macroscopic quantum physics. We propose a measurement-based protocol to herald delocalized, nonclassical states of a mechanical oscillator in cavity optomechanics by conditioning on Geiger photodetection of the optical output. We analyse under which conditions Stokes-induced optomechanical entanglement give rise to mechanical Wigner Function negativity upon detection. We develop and compare a blue-detuned pulsed scheme and a continuous-wave steady-state scheme employing temporal-mode filtering, and we quantify heralding rates and robustness to finite temperature under realistic detection efficiencies.