Quantum squeezing of motion in a mechanical resonator

TLDR

Quantum mechanics predicts that a harmonic oscillator’s ground state exhibits unavoidable zero‑point motion, but these fluctuations can be manipulated. Using microwave radiation pressure, the authors produced a stationary quadrature‑squeezed state of a micrometer‑scale resonator with variance 0.80 of the ground state and performed phase‑sensitive back‑action‑evading measurements, demonstrating relevance for large‑scale quantum state engineering, decoherence studies, and ultrasensitive sensing.

Abstract

According to quantum mechanics, a harmonic oscillator can never be completely at rest. Even in the ground state, its position will always have fluctuations, called the zero-point motion. Although the zero-point fluctuations are unavoidable, they can be manipulated. Using microwave frequency radiation pressure, we have manipulated the thermal fluctuations of a micrometer-scale mechanical resonator to produce a stationary quadrature-squeezed state with a minimum variance of 0.80 times that of the ground state. We also performed phase-sensitive, back-action evading measurements of a thermal state squeezed to 1.09 times the zero-point level. Our results are relevant to the quantum engineering of states of matter at large length scales, the study of decoherence of large quantum systems, and for the realization of ultrasensitive sensing of force and motion.