Quantum sensing with nanoparticles for gravimetry; when bigger is better

TL;DR

This paper discusses the potential of optically levitated nanoparticles as quantum sensors for gravimetry, highlighting their large mass, quantum noise limits, and ability to create superpositions for enhanced sensitivity.

Contribution

It introduces the concept of using macroscopic levitated nanoparticles for quantum gravimetry and evaluates their potential advantages over existing quantum sensors.

Findings

Potential sensitivity of $10^{-15}$ m/s$^2$ for acceleration sensing

Feasibility of implementing long-lived quantum superpositions

Commercial prospects for nanoparticle-based quantum sensors

Abstract

Following the first demonstration of a levitated nanosphere cooled to the quantum ground state in 2020 [1], macroscopic quantum sensors are seemingly on the horizon. The nanosphere's large mass as compared to other quantum systems enhances the susceptibility of the nanoparticle to gravitational and inertial forces. In this viewpoint we describe the features of experiments with optically levitated nanoparticles [2] and their proposed utility for acceleration sensing. Unique to the levitated nanoparticle platform is the ability to implement not only quantum noise limited transduction, predicted by quantum metrology to reach sensitivities on the order of $10^{-15}$ms$^{-2}$ [3], but also long-lived quantum spatial superpositions for enhanced gravimetry. This follows a global trend in developing sensors, such as cold-atom interferometers, that exploit superposition or entanglement. Thanks to significant commercial development of these existing quantum technologies, we discuss the feasibility of translating levitated nanoparticle research into applications.