Direct Detection of Classically Undetectable Dark Matter through Quantum Decoherence

TL;DR

This paper proposes a novel method for directly detecting low-mass dark matter by observing quantum decoherence effects in matter interferometry, offering a new avenue beyond classical detection techniques.

Contribution

It introduces quantum decoherence as a detection mechanism for dark matter below 1 MeV, highlighting the potential of matter interferometry as a sensitive, directional detection method.

Findings

Quantum superpositions are sensitive to low-mass dark matter.

Matter interferometry can serve as a directional detector for galactic dark matter.

The approach provides a new independent detection channel for elusive dark matter.

Abstract

Although various pieces of indirect evidence about the nature of dark matter have been collected, its direct detection has eluded experimental searches despite extensive effort. If the mass of dark matter is below 1 MeV, it is essentially imperceptible to conventional detection methods because negligible energy is transferred to nuclei during collisions. Here I propose directly detecting dark matter through the quantum decoherence it causes rather than its classical effects such as recoil or ionization. I show that quantum spatial superpositions are sensitive to low-mass dark matter that is inaccessible to classical techniques. This provides new independent motivation for matter interferometry with large masses, especially on spaceborne platforms. The apparent dark matter wind we experience as the Sun travels through the Milky Way ensures interferometers and related devices are directional detectors, and so are able to provide unmistakable evidence that decoherence has galactic origins.