Experimental Realisation of a Thermal Squeezed State of Levitated Optomechanics

TL;DR

This paper demonstrates the experimental generation of a thermal squeezed state in a levitated optomechanical system through rapid frequency switching, achieving up to 2.7dB of squeezing in a classical regime.

Contribution

It introduces a novel method for squeezing thermal states of levitated particles via fast frequency switching, with potential for reaching quantum squeezing levels.

Findings

Achieved 2.7dB squeezing of a thermal state

Demonstrated classical regime operation with many thermal excitations

Proposed method for reaching quantum squeezing with ground state cooling

Abstract

We experimentally squeeze the thermal motional state of an optically levitated nanosphere, by fast switching between two trapping frequencies. The measured phase space distribution of our particle shows the typical shape of a squeezed thermal state, from which we infer up to 2.7dB of squeezing along one motional direction. The experiment features a large number of thermal excitations, therefore remaining in the classical regime. Nevertheless, we argue that the manipulation scheme described here could be used to achieve squeezing below the zero-point level, if preceded by ground state cooling of the levitated mechanical oscillator. Additionally, a higher degree of squeezing could in principle be achieved by repeating the frequency-switching protocol multiple times.