Fundamental quantum limits for detecting ultrahigh frequency gravitational waves
Phys. Rev. D 113, 044020 – Published 9 February, 2026
DOI: https://doi.org/10.1103/2w9f-yy8g
Abstract
The ultrahigh frequency (above 10 kHz) gravitational wave (GW) window provides a unique opportunity to detect primordial GWs, free from astrophysical foregrounds that dominate lower frequencies. A stochastic GW background in this range is generically predicted from cosmological phase transitions and topological defects associated with grand unification and other ultrahigh energy theories. We establish a universal quantum limit framework for various detection schemes, setting a fundamental bound on GW detectability. Our analysis reveals that backgrounds in the kHz–MHz range are in principle observable, whereas higher-frequency signals lie below the quantum limit. These results offer theoretical guidance for future detector designs and open new avenues for probing early universe physics.
