Paper

{
  "raw_xml": "<entry>\n    <id>http://arxiv.org/abs/2603.02493v1</id>\n    <title>Probing Planck-Scale Physics with High-Frequency Gravitational Waves</title>\n    <updated>2026-03-03T00:52:57Z</updated>\n    <link href='https://arxiv.org/abs/2603.02493v1' rel='alternate' type='text/html'/>\n    <link href='https://arxiv.org/pdf/2603.02493v1' rel='related' title='pdf' type='application/pdf'/>\n    <summary>We develop a framework for testing quantum gravity through the stochastic gravitational-wave background produced by evaporating near-Planck-mass primordial black holes. Because gravitons free-stream from the emission region without rescattering, they preserve a direct spectral record of the black-hole temperature--mass relation $T(M)$, a relation that is erased for all other Hawking-radiated species by rapid thermalization. We translate six representative phenomenological beyond-semiclassical frameworks (the generalized uncertainty principle, loop quantum gravity, noncommutative geometry, asymptotic safety, string/Hagedorn physics, and tunneling backreaction) into distinct $T(M)$ parametrizations and compute the resulting gravitational wave spectra numerically. Modifications that suppress $T(M)$ shift the spectral peak by up to ten decades in frequency, in some cases into the sensitivity bands of next-generation interferometers or resonant-cavity detectors, while models imposing a hard evaporation cutoff produce distinctive peak morphologies that discriminate between quantum-gravity scenarios. We further discuss the impact of different choices for post-inflationary conditions in the very early universe. We find that the relative spectral displacement between the standard Hawking prediction and any modified model is cosmology-independent, hence spectral shape rather than absolute peak frequency provides the cleanest probe of Planck-scale physics.</summary>\n    <category scheme='http://arxiv.org/schemas/atom' term='hep-ph'/>\n    <category scheme='http://arxiv.org/schemas/atom' term='astro-ph.HE'/>\n    <category scheme='http://arxiv.org/schemas/atom' term='gr-qc'/>\n    <category scheme='http://arxiv.org/schemas/atom' term='hep-th'/>\n    <published>2026-03-03T00:52:57Z</published>\n    <arxiv:comment>26 pages, 6 figures</arxiv:comment>\n    <arxiv:primary_category term='hep-ph'/>\n    <author>\n      <name>Stefano Profumo</name>\n      <arxiv:affiliation>University of California, Santa Cruz</arxiv:affiliation>\n    </author>\n  </entry>"
}