Tricritical directed percolation

TL;DR

This paper investigates a modified contact process with higher-order reactions, revealing a complex phase diagram with tricritical points and analyzing the associated scaling behavior and critical exponents.

Contribution

It introduces a new variant of the contact process that exhibits tricritical behavior and provides a detailed analysis of its phase transitions and universal properties.

Findings

Identification of a tricritical point separating different phase transition lines

Determination of critical exponents and universal scaling functions

Analysis of the phase diagram with higher-order reaction terms

Abstract

We consider a modification of the contact process incorporating higher-order reaction terms. The original contact process exhibits a non-equilibrium phase transition belonging to the universality class of directed percolation. The incorporated higher-order reaction terms lead to a non-trivial phase diagram. In particular, a line of continuous phase transitions is separated by a tricritical point from a line of discontinuous phase transitions. The corresponding tricritical scaling behavior is analyzed in detail, i.e., we determine the critical exponents, various universal scaling functions as well as universal amplitude combinations.