Quantum optomechanics beyond the quantum coherent oscillation regime

Kiran E Khosla,Warwick P Bowen,George A Brawley,Michael R Vanner

doi:10.1364/optica.4.001382

Abstract

Interaction with a thermal environment decoheres the quantum state of a mechanical oscillator. When the interaction is sufficiently strong, such that more than one thermal phonon is introduced within a period of oscillation, quantum coherent oscillations are prevented. This is generally thought to preclude a wide range of quantum protocols. Here, we introduce a pulsed optomechanical protocol that allows ground state cooling, general linear quantum non-demolition measurements, optomechanical state swaps, and quantum state preparation and tomography without requiring quantum coherent oscillations. Finally we show how the protocol can break the usual thermal limit for sensing of impulse forces.

Highlights

We show that by applying a pulsed optomechanics protocol, ground state cooling, general linear back-action evading measurements, state swaps, and non-classical state preparation and quantum tomography are all possible outside the quantum coherent oscillation (QCO) regime
We will show that a sequence of such pulsed interactions, allows arbitrary mechanical quadrature measurements which are sufficient for quantum state tomography, squeezed state preparation, and pulsed optomechanical state swaps [40]
Summary — We have introduced a protocol to realize quantum optomechanics beyond the QCO regime, where quantum state preparation and direct tomography are possible within a fraction of a mechanical period

Summary

Introduction

We show that by applying a pulsed optomechanics protocol, ground state cooling, general linear back-action evading measurements, state swaps, and non-classical state preparation and quantum tomography are all possible outside the QCO regime. Under these conditions the unitary describing the total pulsed interaction [√16] is given by U (XM√, XL) = exp[−iλXMXL], where 2XM = b + b† and 2XL = a + a† are the mechanical position and optical amplitude quadratures, respectively.

Results

Conclusion