Nanomechanical sensor resolving impulsive forces below its zero-point fluctuations

TL;DR

This paper demonstrates a quantum-limited nanomechanical sensor using an optically levitated nanoparticle, capable of detecting impulsive forces below its zero-point fluctuations by employing reversible squeezing to amplify weak signals.

Contribution

It introduces a novel method of using reversible squeezing of a levitated nanoparticle's motion to enhance sensitivity beyond quantum limits for impulsive force detection.

Findings

Resolved impulsive forces as small as 6.9 keV/c

Achieved detection below the zero-point fluctuation level

Demonstrated quantum-limited force sensing with a levitated nanoparticle

Abstract

The sensitivity of a mechanical transducer is ultimately limited by its inherent quantum fluctuations. Here, we use an optically levitated nanoparticle to measure impulsive forces smaller than the particle's zero-point momentum uncertainty. Our approach relies on reversibly squeezing the levitated particle's center-of-mass motion to coherently amplify the perturbation. We demonstrate resolving single impulsive-force kicks as small as 6.9 keV/c, a value 0.6 dB below the sensor's zero-point value.