English

Is there a conflict between causality and diamagnetism?

Quantum Physics 2025-11-06 v3 Materials Science Other Condensed Matter Optics

Abstract

There is a long-standing apparent conflict between the existence of diamagnetism and causality as expressed through the Kramers-Kronig relations. In essence, using causality arguments, along with a small number of seemingly well-justified assumptions, one can show that diamagnetism is impossible. However, experiments show diamagnetic responses from magnetic media. We present a resolution to this issue, which also explains the absence of observed dia-electric responses in media. In the process, we expose some of the short-comings in earlier analyses that have kept the paradox alive.

Cite

@article{arxiv.2501.13098,
  title  = {Is there a conflict between causality and diamagnetism?},
  author = {Niclas Westerberg and Stephen M. Barnett},
  journal= {arXiv preprint arXiv:2501.13098},
  year   = {2025}
}

Comments

12 pages + appendices, 2 figures. Published version

R2 v1 2026-06-28T21:13:58.303Z