Infinite-randomness critical point in the two-dimensional disordered contact process

Abstract

We study the nonequilibrium phase transition in the two-dimensional contact process on a randomly diluted lattice by means of large-scale Monte-Carlo simulations for times up to $10^{10}$ and system sizes up to $8000\times 8000$ sites. Our data provide strong evidence for the transition being controlled by an exotic infinite-randomness critical point with activated (exponential) dynamical scaling. We calculate the critical exponents of the transition and find them to be universal, i.e., independent of disorder strength. The Griffiths region between the clean and the dirty critical points exhibits power-law dynamical scaling with continuously varying exponents. We discuss the generality of our findings and relate them to a broader theory of rare region effects at phase transitions with quenched disorder. Our results are of importance beyond absorbing state transitions because according to a strong-disorder renormalization group analysis, our transition belongs to the universality class of the two-dimensional random transverse-field Ising model.

13 pages, 12 eps figures, final version as published

References in corpus (7)

• Applications of Field-Theoretic Renormalization Group Methods to Reaction-Diffusion Problems
• Directed percolation criticality in turbulent liquid crystals
• Quantum Griffiths effects in itinerant Heisenberg magnets
• Critical behavior and Griffiths effects in the disordered contact process
• Contact process on a Voronoi triangulation
• Weakly disordered absorbing-state phase transitions
• Multicritical behavior of the diluted contact process

Cited by in corpus (1)

• Absorbing-state phase transitions on percolating lattices