Critical dynamics within the real-time FRG approach

Abstract

The Schwinger-Keldysh functional renormalization group developed by Y.-y. Tan [Real-time dynamics of the O(4) scalar theory within the fRG approach, ] is employed to investigate critical dynamics related to a second-order phase transition. The effective action of model A is expanded to the order of O(∂2) in the derivative expansion for the O(N) symmetry. By solving the fixed-point equations of effective potential and wave function, we obtain static and dynamic critical exponents for different values of the spatial dimension d and the field component number N. It is found that one has z≥2 in the whole range of 2≤d≤4 for the case of N=1, while in the case of N=4, the dynamic critical exponent turns to z<2 when the dimension approach towards d=2. Published by the American Physical Society 2024