Quantum Back Action Evasion with Reservoir Engineering

TL;DR

This paper introduces a novel reservoir engineering approach to achieve quantum back-action evasion in optomechanical systems, surpassing the standard quantum limit by measuring velocity through reciprocal interactions.

Contribution

It demonstrates that reservoir engineering can replicate nonreciprocal velocity measurement schemes, enabling back-action evasion with only reciprocal interactions.

Findings

Force sensitivity exceeds the standard quantum limit

Reservoir engineering reproduces double-pass speed meter behavior

Method provides an alternative to nonreciprocal coupling in quantum measurements

Abstract

We propose a back-action evading scheme for a free mass that combines reservoir engineering with velocity measurement. The underlying principle follows the double-pass-type speed meter, which measures the mirror's velocity using a nonreciprocal interaction. In our method, the nonreciprocal coupling is realized through reservoir engineering, following the recipe proposed in [Phys. Rev. X 5, 021025]. We show that reservoir engineering can reproduce the double-pass speed meter with optimal feedforward, using only reciprocal interactions. The resulting force sensitivity surpasses the standard quantum limit, providing an alternative route to quantum back-action evasion in cavity optomechanical systems.