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arXiv:2601.21119

A levitated nano-accelerometer sensitized by quantum quench

M. Kamba, S. Otabe, K. Funo, T. Sagawa, K. Aikawa

quant-phphysics.opticsSubmitted Jan 28, 2026• Announced Jan 30, 2026• 0 citations
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Abstract

We realize a nanoscale accelerometer exploiting the nonequilibrium dynamics of a nanoparticle near the quantum ground state. We explore the dynamics after quenching the trapping potential and find that rapid quenching provides an instance at which the sensitivity is enhanced due to the minimized uncertainty in the position. With rapid quenching, the observed sensitivity is in good agreement with a numerical simulation based on the quantum Langevin equation and approaches to the limit given by the quantum Fisher information. Our results open up a pathway to quantum inertial sensing sensitized by exploiting quench dynamics.

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11 pages, 7 figures

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We realize a nanoscale accelerometer exploiting the nonequilibrium dynamics of a nanoparticle near the quantum ground state. We explore the dynamics after quenching the trapping potential and find that rapid quenching provides an instance at which the sensitivity is enhanced due to the minimized uncertainty in the position. With rapid quenching, the observed sensitivity is in good agreement with a numerical simulation based on the quantum Langevin equation and approaches to the limit given by the quantum Fisher information. Our results open up a pathway to quantum inertial sensing sensitized by exploiting quench dynamics.
We realize a nanoscale accelerometer with a levitated nanoparticle near the ground state, exploiting its dynamical behavior triggered by the abrupt quench of its trapping potential. We find that rapid quenching provides a readout time at which the sensitivity is enhanced by 2 orders of magnitude with a favorable combination of a large acceleration-induced displacement and a reduced position uncertainty, enabling us to detect a weak acceleration obscured by the zero-point fluctuation in the initial potential. With rapid quenching, the observed sensitivity is in good agreement with a numerical simulation based on the quantum Langevin equation. Our results provide a step toward inertial sensing with levitated nanoparticles through time-optimal quench dynamics in the quantum regime.
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Manipulating the motion of macroscopic objects near their quantum mechanical uncertainties has been desired in diverse fields, including fundamental physics, sensing, and transducers. Despite progress in ground-state cooling of a levitated solid particle, realizing its nonclassical states has been elusive. Here, we demonstrate quantum squeezing of the motion of a single nanoparticle by rapidly varying its oscillation frequency. We reveal appreciable narrowing of the velocity variance to -4.9 ± 0.1 decibels of that of the ground state using free-expansion measurements. Our work shows that a levitated nanoparticle offers an ideal platform for studying nonclassical states of its motion and provides a route to developing applications in quantum sensing and exploring quantum mechanics at a macroscopic scale.
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ABSTRACT Levitodynamics, i.e., the levitation of objects of mesoscopic size has made huge progress in the last decade allowing to address some questions of fundamental physics for the first time. It has become possible to cool a levitated particle of mesoscopic size down to its motional ground state and to observe its motion driven by quantum fluctuations. This defines a quantum system that is ideally suited for an analysis within Nelson's stochastic mechanics approach to quantum mechanics, which allows for a dynamic description of individual particle paths. In good approximation, a levitated nanoparticle is a quantum harmonic oscillator. The coherent states of such an oscillator are superpositions of classical paths and the stochastic ground state process. They are exact solutions not only of the Schrödinger equation but also of the quantum Hamilton equations of Nelson's stochastic mechanics, and they are amenable to path simulations. All model parameters are typically available from experiment. Analyzing the quantum motion of the levitated nanoparticle in terms of the coherent states of a quantum harmonic oscillator allows for a quantitative prediction of the experimentally measured power spectral density of its position fluctuations and predicts new experimentally accessible measures for the mean number of phonons present in the center of mass motion. It also explains the observed phase space trajectory of the nano‐particle during cooling.