Diffusion Disorder In The Contact Process
Abstract
We study the effects of spatially inhomogeneous diffusion on the nonequilibrium phase transition in the unidimensional contact process. The directed-percolation critical point in the contact process is known to be stable against the addition of a spatially uniform diffusion term. Correspondingly, we find quenched randomness in the diffusion rates to be irrelevant by power counting in the field theory of the contact process. However, large-scale Monte Carlo simulations demonstrate that such diffusion disorder destabilizes the clean directed percolation critical point. Instead, the transition belongs to the same infinite-randomness universality class as the contact process with disorder in the infection or healing rates. To explain these results, we develop an effective model with an infinite diffusion rate; it shows that diffusion disorder generates an effective disorder in the healing rates. The same mechanism also appears in the field-theoretic description: Whereas diffusion disorder is irrelevant by power-counting, it generates standard random-mass disorder under renormalization. We discuss the validity of this mechanism at higher dimensions and for other absorbing state transitions and nonequilibrium phase transitions in general.
Recommended Citation
V. Anfray et al., "Diffusion Disorder In The Contact Process," Physical Review E, vol. 114, no. 3, article no. 034112, American Physical Society, Sep 2026.
The definitive version is available at https://doi.org/10.1103/73g3-b38r
Department(s)
Physics
International Standard Serial Number (ISSN)
2470-0053; 2470-0045
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2026 American Physical Society, All rights reserved.
Publication Date
01 Sep 2026
Comments
National Science and Technology Council, Grant NSTC 111-2112-M-001-027-MY3