Direct limits for scalar field dark matter from a gravitational-wave detector

S M Vermeulen ,K Danzmann ,P Relton ,B Sorazu ,H Lück ,H Vahlbruch ,E Schreiber ,M Mehmet ,S Doravari ,J D Lough ,F Bergamin ,M Weinert ,V Raymond ,M Brinkmann ,K A Strain ,C Affeldt ,V Kringel ,A Bisht ,H Grote ,B Willke ,N Mukund ,S L Nadji ,H Wittel

doi:10.1038/s41586-021-04031-y

Abstract

The nature of dark matter remains unknown to date, although several candidate particles are being considered in a dynamically changing research landscape1. Scalar field dark matter is a prominent option that is being explored with precision instruments, such as atomic clocks and optical cavities2–8. Here we describe a direct search for scalar field dark matter using a gravitational-wave detector, which operates beyond the quantum shot-noise limit. We set new upper limits on the coupling constants of scalar field dark matter as a function of its mass, by excluding the presence of signals that would be produced through the direct coupling of this dark matter to the beam splitter of the GEO600 interferometer. These constraints improve on bounds from previous direct searches by more than six orders of magnitude and are, in some cases, more stringent than limits obtained in tests of the equivalence principle by up to four orders of magnitude. Our work demonstrates that scalar field dark matter can be investigated or constrained with direct searches using gravitational-wave detectors and highlights the potential of quantum-enhanced interferometry for dark matter detection.

Highlights

In this work, we conduct a direct search for scalar field dark matter using a gravitational-wave detector, the quantum-enhanced GEO600 interferometer, and set new upper limits on the parameters of such dark matter
As non-zero velocities produce a Doppler shift of the observed dark matter field frequency, this virialization results in the dark matter field having a finite coherence time or, equivalently, a spread in observed frequency . 17,21 The linewidth is determined by the virial velocity, which is given by the depth of the gravitational potential
We presented a search for signals of scalar field dark matter in the data of a gravitational-wave detector

Summary

Introduction

We conduct a direct search for scalar field dark matter using a gravitational-wave detector, the quantum-enhanced GEO600 interferometer, and set new upper limits on the parameters of such dark matter. Where ωφ = (mφc2)/ħ is the angular Compton frequency and kφ = (mφvobs)/ħ is the wave vector, with mφ the mass of the field and vobs the velocity relative to the observer. These models predict that such dark matter would be trapped and virialized in gravitational potentials, leading to a Maxwell– Boltzmann-like distribution of velocities vobs relative to an observer. Certain kinds of scalar particles, such as relaxion dark matter , 22,23 may form gravitationally bound objects and be captured in the gravitational potential of the Earth or the Sun, producing a local dark matter overdensity where the field has a much narrower linewidth[24]. Scalar field dark matter could couple to the fields of the standard model (SM) in numerous ways. Sometimes called a ‘portal’, is modelled by the addition of a parameterized interaction

Methods

Results

Conclusion