Double transitions, non-Ising criticality and critical absorbing phase in an interacting monomer-dimer model on a square lattice:

TL;DR

This study investigates an interacting monomer-dimer model on a square lattice, revealing two close continuous transitions with unique critical behaviors, including non-Ising criticality and persistent critical decay within the absorbing phase.

Contribution

It uncovers the coexistence of a non-Ising symmetry-breaking transition and a directed percolation absorbing transition, highlighting novel critical phenomena in the model.

Findings

Non-Ising critical behavior at the symmetry-breaking transition

Persistent critical decay of dimer density in the absorbing phase

Identification of two nearby continuous phase transitions

Abstract

We present a numerical study on an interacting monomer-dimer model with nearest neighbor repulsion on a square lattice, which possesses two symmetric absorbing states. The model is observed to exhibit two nearby continuous transitions: the $Z_2$ symmetry-breaking order-disorder transition and the absorbing transition with directed percolation criticality. We find that the symmetry-breaking transition shows a non-Ising critical behavior, and that the absorbing phase becomes critical, in the sense that the critical decay of the dimer density observed at the absorbing transition persists even within the absorbing phase. Our findings call for further studies on the microscopic models and corresponding continuum description belonging to the generalized voter universality class.