The universe as a superconductor: How to search for a photon mass
Abstract
We revisit the bounds on the photon mass when it arises from an Abelian Higgs mechanism rather than a Proca term. Because the higgs is necessarily millicharged and light, the phase of the theory (Meissner, vortex, or symmetry-restored) depends on the ambient magnetic field, so the photon mass an experiment measures depends on the environment it is performed in. We classify existing experiments by the phases in which they apply, in analogy with Type I and Type II superconductors. For Type I photon masses, magnetic fields in galaxies and the intergalactic medium can restore the symmetry everywhere, allowing a vacuum photon mass as large as 0.3 MeV. Regions of photon mass as large as 10−5 eV could be present in the Universe, and measurement of frequency dependent optical depth can potentially reveal these regions. For Type II photon masses, we show that the strongest constraints mainly arise from the requirement that the galactic dynamo generates the observed magnetic fields, which we derive by generalizing magnetohydrodynamics to a nonzero photon mass. Since the terrestrial magnetic field restores the symmetry in much of the remaining parameter space, laboratory searches performed inside large magnetically shielded volumes, or in space, could probe photon masses invisible to any experiment on Earth. Measurements of distant light sources, in particular, fast radio bursts, also offer unique sensitivity to parameters invisible to lab experiments.
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BibTeX
@misc{gruzinov2026universe,
title = {{The universe as a superconductor: How to search for a photon mass}},
author = {Andrei Gruzinov and Anson Hook and Junwu Huang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.26888},
eprint = {2609.26888},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.26888},
}
RIS
TY - UNPB
TI - The universe as a superconductor: How to search for a photon mass
AU - Andrei Gruzinov
AU - Anson Hook
AU - Junwu Huang
PY - 2026
DA - 2026/09/22
PB - arXiv
DO - 10.48550/arxiv.2609.26888
UR - https://arxiv.org/abs/2609.26888
AB - We revisit the bounds on the photon mass when it arises from an Abelian Higgs mechanism rather than a Proca term. Because the higgs is necessarily millicharged and light, the phase of the theory (Meissner, vortex, or symmetry-restored) depends on the ambient magnetic field, so the photon mass an experiment measures depends on the environment it is performed in. We classify existing experiments by the phases in which they apply, in analogy with Type I and Type II superconductors. For Type I photon masses, magnetic fields in galaxies and the intergalactic medium can restore the symmetry everywhere, allowing a vacuum photon mass as large as 0.3 MeV. Regions of photon mass as large as 10^−5 eV could be present in the Universe, and measurement of frequency dependent optical depth can potentially reveal these regions. For Type II photon masses, we show that the strongest constraints mainly arise from the requirement that the galactic dynamo generates the observed magnetic fields, which we derive by generalizing magnetohydrodynamics to a nonzero photon mass. Since the terrestrial magnetic field restores the symmetry in much of the remaining parameter space, laboratory searches performed inside large magnetically shielded volumes, or in space, could probe photon masses invisible to any experiment on Earth. Measurements of distant light sources, in particular, fast radio bursts, also offer unique sensitivity to parameters invisible to lab experiments.
ER -