Pressure-Tunable Targets for Light Dark Matter Direct Detection: The Case of Solid Helium

TL;DR

This paper explores using hydrostatic pressure to tune solid helium as a target for light dark matter detection via phonons, showing pressure enhances phonon properties to improve detection sensitivity.

Contribution

It introduces pressure as a novel tuning parameter for solid helium in dark matter detection, demonstrating how high pressure extends the phonon energy range.

Findings

High pressure increases helium's phonon frequencies.

Pressure enables helium to probe lower dark matter masses.

Solid helium's suitability improves with pressure tuning.

Abstract

We propose hydrostatic pressure -- a well-established tool for tuning properties of condensed matter -- as a novel route for optimizing targets for light dark matter direct detection, specifically via phonons. Pressure dramatically affects compressible solids by boosting the speed of sound and phonon frequencies. Focusing on helium -- the most compressible solid -- our ab initio calculations illustrate how high pressure elevates helium from lacking single-phonon reach to rivaling leading candidates. Our work establishes pressure as an unexplored tuning knob for accessing lower dark matter mass regimes.