Nonequilibrium critical relaxation of structurally disordered systems in the short-time regime: Renormalization group de
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SORDER, AND PHASE TRANSITION IN CONDENSED SYSTEM
Nonequilibrium Critical Relaxation of Structurally Disordered Systems in the ShortTime Regime: Renormalization Group Description and Computer Simulation V. V. Prudnikov, P. V. Prudnikov, I. A. Kalashnikov, and M. V. Rychkov Omsk Dostoevsky State University, Omsk, 644077 Russia email: [email protected] Received August 3, 2009
Abstract—The influence of nonequilibrium initial states on the evolution of anisotropic systems with quenched uncorrelated structural defects at the critical point is studied. The fieldtheoretical description of the nonequilibrium critical behavior of 3D systems is obtained for the first time, and the dynamic critical exponent of the shorttime evolution in the twoloop approximation without the use of ε expansion is calculated. The values of dynamic critical exponents calculated using the series resummation methods are compared with the results of computer simulation of nonequilibrium critical behavior of the 3D disordered Ising model in the shorttime regime. It is demonstrated that the values of the critical exponents calculated in this paper are in better agreement with the results of computer simulation than the results of application of ε expansion. DOI: 10.1134/S1063776110020093
1. INTRODUCTION We study how the effects of violation of the space translation symmetry of the system created by struc tural defects and how the effects of violation of the timetranslation symmetry due to nonequilibrium ini tial conditions of the system simultaneously influence the characteristics of the anomalously slow nonequi librium critical behavior of different systems. In recent years, the investigation of systems char acterized by slow dynamics has led to considerable interest from both the theoretical and experimental points of view. This is due to the predicted and observed, in the case of slow evolution of systems from the nonequilibrium initial state, ageing properties which are characterized by violations in the fluctua tion–dissipative theorem. Wellknown examples of such systems exhibiting slow dynamics and ageing effects are complex disordered systems like spin glasses [1, 2]. However, it was demonstrated by different ana lytical and numerical studies [3, 4] that these specific features of nonequilibrium behavior can be observed in common systems with the secondorder phase tran sitions since their critical dynamics is characterized by anomalously large relaxation times. Note that the fluctuation–dissipative ratio connecting the twotime spin response function and the twotime correlation function and generalizing the fluctuation–dissipative theorem to the case of nonequilibrium behavior intro duced earlier for spin glasses is a new universal charac teristic for the critical behavior of various systems [5]. In the past decade, considerable progress has been achieved in understanding and describing the non
equilibrium critical behavior of macroscopic systems far from equilibrium. This is primarily related to phe nomena of criti
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