Steady-state negative Wigner functions of nonlinear nanomechanical oscillators

TL;DR

This paper presents a method to prepare nanomechanical oscillators in nonclassical steady states with negative Wigner functions by enhancing nonlinearity and selectively addressing phonon states using optomechanical coupling.

Contribution

The authors introduce a scheme to generate nonclassical steady states in nanomechanical oscillators through enhanced nonlinearity and spectral addressing of phonon states.

Findings

Enables preparation of single phonon Fock states.

Achieves negative Wigner functions indicating nonclassical states.

Applicable to carbon nanotube coupled with microcavity.

Abstract

We propose a scheme to prepare nanomechanical oscillators in nonclassical steady states, characterized by a pronounced negative Wigner function. In our optomechanical approach, the mechanical oscillator couples to multiple laser driven resonances of an optical cavity. By lowering the resonance frequency of the oscillator via an inhomogeneous electrostatic field, we significantly enhance its intrinsic geometric nonlinearity per phonon. This causes the motional sidebands to split into separate spectral lines for each phonon number and transitions between individual phonon Fock states can be selectively addressed. We show that this enables the preparation of the nanomechanical oscillator in a single phonon Fock state. Our scheme can for example be implemented with a carbon nanotube dispersively coupled to the evanescent field of a state of the art whispering gallery mode microcavity.