Six universality classes govern the critical and multicritical behavior of an active Ising
model
model
File(s)
Published version
Author(s)
Wong, Matthew
Lee, Chiu Fan
Type
Journal Article
Abstract
The critical behavior of the equilibrium Ising model, famously governed by the Wilson-Fisher universality class (UC), is a cornerstone of statistical physics. A natural question is whether its properties are modified when the interacting spins are allowed to move. This can be explored within the framework of active motility by, e.g., prescribing that the spins self-propel along the direction of their orientation. In such a system, the spin number density necessarily constitutes a soft hydrodynamic mode and can therefore modify the scaling behavior. In this letter, we show that this is indeed the case in a critical active Ising model where density impedes the system's collective motion. Using a perturbative dynamic renormalization group analysis at a one-loop level, We identify six UCs, including three previously unidentified ones, one of which supersedes the Wilson–Fisher UC as the generic UC governing the critical behavior.
Date Issued
2026-08-01
Date Acceptance
2026-07-13
Citation
Physical Review E: Statistical, Nonlinear, and Soft Matter Physics, 2026, 114 (2)
ISSN
1539-3755
Publisher
American Physical Society
Journal / Book Title
Physical Review E: Statistical, Nonlinear, and Soft Matter Physics
Volume
114
Issue
2
Copyright Statement
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
License URL
Identifier
10.1103/wgym-kkzz
Publication Status
Published
Article Number
L022103
Date Publish Online
2026-08-13