Probing imperfect axions with nuclear clocks
Abstract
We show that 229Th nuclear clocks can probe departures from the Peccei-Quinn (PQ) solution to the strong CP problem. Explicit PQ breaking or additional CP-violating interactions can shift the minimum of the axion potential and generate CP-violating couplings to matter, inducing a clock response linear in the axion field. We investigate explicit PQ breaking and quark chromo-electric dipole operators as representative realizations of these \textit{imperfect axion} scenarios, consistent with electric dipole moment constraints. For axion dark matter, the linear signal oscillates at the Compton frequency and can dominate the quadratic response. Even without axion dark matter, the Earth can source a static axion field, enabling fifth-force searches with nuclear clocks.
Related
BibTeX
@misc{bottaro2026probing,
title = {{Probing imperfect axions with nuclear clocks}},
author = {Salvatore Bottaro and Andrea Caputo and Gilad Perez and Yotam Soreq and Alfredo Stanzione},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.30238},
eprint = {2610.30238},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.30238},
}
RIS
TY - UNPB
TI - Probing imperfect axions with nuclear clocks
AU - Salvatore Bottaro
AU - Andrea Caputo
AU - Gilad Perez
AU - Yotam Soreq
AU - Alfredo Stanzione
PY - 2026
DA - 2026/10/21
PB - arXiv
DO - 10.48550/arxiv.2610.30238
UR - https://arxiv.org/abs/2610.30238
AB - We show that ^229Th nuclear clocks can probe departures from the Peccei-Quinn (PQ) solution to the strong CP problem. Explicit PQ breaking or additional CP-violating interactions can shift the minimum of the axion potential and generate CP-violating couplings to matter, inducing a clock response linear in the axion field. We investigate explicit PQ breaking and quark chromo-electric dipole operators as representative realizations of these \textit{imperfect axion} scenarios, consistent with electric dipole moment constraints. For axion dark matter, the linear signal oscillates at the Compton frequency and can dominate the quadratic response. Even without axion dark matter, the Earth can source a static axion field, enabling fifth-force searches with nuclear clocks.
ER -