Unveiling the hidden weak universality of the Ziff-Gulari-Barshad model.

Abstract

In this work, we revisited the Ziff-Gullari-Barshad (ZGB) model in order to investigate its critical behavior when carbon monoxide (CO) molecules are allowed to desorb from the catalytic surface. As shown by several authors, when this kind of desorption takes place, the first-order phase transition of the standard model disappears, and an Ising-like critical point is found for a very small value of the desorption rate. However, our time-dependent Monte Carlo simulations reveal that, instead of a single critical point, there exists a critical line that appears to encompass multiple universality classes, passing through the Ising and three-state Potts points, as well as providing reasonable evidence for the four-state Potts point, resulting in an unprecedented critical line exhibiting weak universality.