Levitated Nano-accelerometer Sensitized by Quantum Quench.

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.