Search for Dark Matter Scattering from Optically Levitated Nanoparticles

TL;DR

This paper demonstrates the use of optically levitated nanoparticles as sensitive detectors for dark matter interactions, setting new constraints on dark matter-neutron couplings and highlighting future potential for detecting light dark matter and neutrinos.

Contribution

It introduces a novel application of levitated optomechanical sensors for dark matter detection, achieving new sensitivity limits and demonstrating directional detection capabilities.

Findings

Set upper limits on neutron-dark matter coupling for masses 1-10^7 GeV/c^2.

Demonstrated directional sensitivity to distinguish dark matter signals from backgrounds.

Outlined future prospects for detecting lighter dark matter and neutrinos.

Abstract

The development of levitated optomechanics has enabled precise force sensors that operate in the quantum measurement regime, opening up unique opportunities to search for new physics whose weak interactions may have evaded existing sensors. We demonstrate the detection of impulsive forces acting on optically levitated nanoparticles, where the dominant noise source is provided by measurement backaction. Using these sensors, we search for momentum transfers that may originate from scattering of passing particlelike dark matter. For dark matter that couples to Standard Model neutrons via a generic long-range interaction, this search constrains a range of models in the mass range $1$-$10^7~\mathrm{GeV/}c^2$, placing upper limits on single neutron coupling strength as low as $\leq 1 \times 10^{-7}$ at the 95% confidence level. We also demonstrate the ability of using the inherent directional sensitivity of these sensors to separate possible dark matter signals from backgrounds. Future extensions of the techniques developed here can enable searches for light dark matter and massive neutrinos that can reach sensitivity several orders of magnitude beyond existing searches.