Challenges and Opportunities of Gravitational Wave Searches at MHz to GHz Frequencies

TL;DR

This paper reviews the challenges and potential opportunities in detecting ultra-high-frequency gravitational waves (MHz to GHz), emphasizing the scientific significance, detector concepts, and recent initiatives in this emerging research area.

Contribution

It provides a comprehensive overview of the current state, challenges, and future prospects of high-frequency gravitational wave detection, highlighting new detector concepts and scientific opportunities.

Findings

No known astrophysical sources in MHz-GHz range.

Several detector concepts with varying sensitivities.

Potential to discover new physics beyond the Standard Model.

Abstract

The first direct measurement of gravitational waves by the LIGO and Virgo collaborations has opened up new avenues to explore our Universe. This white paper outlines the challenges and gains expected in gravitational wave searches at frequencies above the LIGO/Virgo band, with a particular focus on Ultra High-Frequency Gravitational Waves (UHF-GWs), covering the MHz to GHz range. The absence of known astrophysical sources in this frequency range provides a unique opportunity to discover physics beyond the Standard Model operating both in the early and late Universe, and we highlight some of the most promising gravitational sources. We review several detector concepts which have been proposed to take up this challenge, and compare their expected sensitivity with the signal strength predicted in various models. This report is the summary of the workshop "Challenges and opportunities of high-frequency gravitational wave detection" held at ICTP Trieste, Italy in October 2019, that set up the stage for the recently launched Ultra-High-Frequency Gravitational Wave (UHF-GW) initiative.