Critical behavior of the Ising model under strong shear: The conserved case

The non-equilibrium phase transitions of the two-dimensional magnetization-conserved Ising model under the action of an external shear field is investigated. This field, that simulates a convective velocity profile with shear rate (gamma) over dot, introduces anisotropic effects and forces the system to evolve into non equilibrium states. By employing the short-time dynamics (STD) methodology, it was possible to detect first- and second-order phase transitions, and in this last case the critical exponent were calculated. As a function of the absolute magnetization vertical bar M vertical bar the system exhibits phase transitions of different order. On the one hand, If vertical bar M vertical bar = 0, the model undergoes a second-order phase transition. The estimated critical temperature T-c depends on (gamma) over dot and two regimes can be distinguished: a power-law regime for low. (gamma) over dot's, and a saturation regime at larger values of it. For the investigated shear field interval, the estimated values of the anisotropic critical exponents suggest that the critical behavior is on a crossover between the Ising and mean-field critical behaviors, respectively. On the other hand if vertical bar M vertical bar > 0, the model exhibits for each (gamma) over dot first-order phase transitions, ending in a critical point at vertical bar M vertical bar = 0. (C) 2021 Elsevier B.V. All rights reserved.