Unconditional preparation of nonclassical states via linear-and-quadratic optomechanics

TL;DR

This paper presents a reservoir engineering method to deterministically prepare nonclassical states of a mechanical oscillator using linear and quadratic optomechanics, without the need for measurement or ground state initialization.

Contribution

It introduces a new scheme for stabilizing nonclassical states via cavity drives on multiple sidebands, enabling unconditional preparation of macroscopic quantum states.

Findings

States include squeezed and displaced superpositions of phonons

The method can generate single-phonon and Schrödinger-cat-like states

It operates without measurement, feedback, or ground state initialization

Abstract

Reservoir engineering enables the robust preparation of pure quantum states in noisy environments. We show how a new family of quantum states of a mechanical oscillator can be stabilized in a cavity that is parametrically coupled to both the mechanical displacement and the displacement squared. The cavity is driven with three tones, on the red sideband, on the cavity resonance and on the second blue sideband. The states so stabilized are (squeezed and displaced) superpositions of a finite number of phonons. They show the unique feature of encompassing two prototypes of nonclassicality for bosonic systems: by adjusting the strength of the drives, one can in fact move from a single-phonon- to a Schrodinger-cat-like state. The scheme is deterministic, supersedes the need for measurement-and-feedback loops and does not require initialization of the oscillator to the ground state. As such, it enables the unconditional preparation of nonclassical states of a macroscopic object.