| Issue |
EPL
Volume 151, Number 2, July 2025
|
|
|---|---|---|
| Article Number | 26001 | |
| Number of page(s) | 5 | |
| Section | Condensed matter and materials physics | |
| DOI | https://doi.org/10.1209/0295-5075/adf3e1 | |
| Published online | 11 August 2025 | |
Is diamagnetism really acausal?
School of Physics and Astronomy, University of Glasgow - Glasgow G12 8QQ, UK
Received: 15 May 2025
Accepted: 24 July 2025
Diamagnetism, in which the magnetisation in a medium opposes the direction of an applied magnetic field, is a weak but familiar effect in a wide class of materials. Being weak it is also a linear response to any applied field. The problem is that the existence of diamagnetism is in direct conflict with the requirements of causality as embodied in the familiar Kramers-Kronig relations. Nature does not care about our confusion and diamagnetism exists and physics is constrained by the requirements of causality (that effect cannot precede its cause). This puzzle has received attention from time to time, with a variety of arguments made to resolve the paradox. None of these, no matter how plausible, reveal the mechanism that resolves the existence of diamagnetism without sacrificing causality. The full resolution is presented in this letter.
© 2025 The author(s)
Published by the EPLA under the terms of the Creative Commons Attribution 4.0 International License (CC-BY). Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.