Force-Gradient Sensing and Entanglement via Feedback Cooling of Interacting Nanoparticles

We show theoretically that feedback cooling of two levitated, interacting nanoparticles enables differential sensing of forces and the observation of stationary entanglement. The feedback drives the two particles into a stationary, nonthermal state which is susceptible to inhomogeneous force fields and which exhibits entanglement for sufficiently strong interparticle couplings. We predict that force-gradient sensing at the zepto-Newton per micron range is feasible and that entanglement due to the Coulomb interaction between charged particles can be realistically observed in state-of-the-art setups.

Automated summary

This study theoretically demonstrates that feedback cooling of two levitated, interacting nanoparticles allows for differential force sensing and the observation of stationary entanglement. The feedback efficiently drives the particles into a stationary, nonthermal state, enabling sensitivity to inhomogeneous force fields and the emergence of entanglement for strong interparticle coupling. The findings suggest the feasibility of force-gradient sensing at zepto-Newton per micron range and the realistic observation of entanglement resulting from Coulomb interaction in state-of-the-art setups.