Published January 2024 | Published
Journal Article Open

Non-standard axion electrodynamics and the dual Witten effect

  • 1. ROR icon University of Massachusetts Amherst
  • 2. ROR icon California Institute of Technology
  • 3. ROR icon Harvard University

Abstract

Standard axion electrodynamics has two closely related features. First, the coupling of a massless axion field to photons is quantized, in units proportional to the electric gauge coupling squared. Second, the equations of motion tell us that a time-dependent axion field in a background magnetic field sources an effective electric current, but a time-dependent axion field in a background electric field has no effect. These properties, which manifestly violate electric-magnetic duality, play a crucial role in experimental searches for axions. Recently, electric-magnetic duality has been used to motivate the possible existence of non-standard axion couplings, which can both violate the usual quantization rule and exchange the roles of electric and magnetic fields in axion electrodynamics. We show that these non-standard couplings can be derived from SL(2,ℤ) duality, but that they come at a substantial cost: in non-standard axion electrodynamics, all electrically charged particles become dyons when the axion traverses its field range, in a dual form of the standard Witten effect monodromy. This implies that there are dyons near the weak scale, leads to a large axion mass induced by Standard Model fermion loops, and dramatically alters Higgs physics. We conclude that non-standard axion electrodynamics, although interesting to consider in abstract quantum field theory, is not phenomenologically viable.

Copyright and License

© The Authors. This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.

Article funded by SCOAP3.

Acknowledgement

MR thanks Prateek Agrawal and John Terning for raising thought-provoking questions (in conversations a few years ago) about how electric-magnetic duality relates to axion physics, and Kevin Zhou for providing references to some of the literature on non-standard formulations of axion electrodynamics. MR also thanks Anton Sokolov for an email exchange, and Eduardo García-Valdecasas for comments on a draft. We thank an anonymous referee for questions and comments that have improved the paper. BH is supported by NSF grant PHY-2112800. JM is supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under Award Number DE-SC0011632. MR is supported in part by the DOE Grant DE-SC0013607 and the NASA Grant 80NSSC20K0506.

Files

JHEP01(2024)120.pdf
Files (853.8 kB)
Name Size Download all
md5:5e410196a9a195baadf12911b2fc2d13
853.8 kB Preview Download

Additional details

Created:
March 17, 2025
Modified:
March 17, 2025