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arXiv · 2601.17849

Geometric noise spectrum in interferometers

Laurent Freidel·Robin Oberfrank
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Abstract

We study the power spectral density of time delay fluctuations in an interferometer as a potential low-energy quantum gravitational observable. We derive a general expression for the spectrum in terms of the Wightman function of linear metric perturbations, which we then apply to a variety of cases. We analyze the intrinsic graviton fluctuations in the vacuum, thermal, and squeezed states, as well as the fluctuations induced by the vacuum stress-energy of a massless scalar field. We find that the resulting spectra are free of ultraviolet divergences and that, while thermal and squeezed states provide a natural amplification mechanism, the spectra remain suppressed by the Planck scale.

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Laurent Freidel, Robin Oberfrank. 2026-01-25. Geometric noise spectrum in interferometers. https://arxiv.org/abs/2601.17849

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