2015/05/27 by G. A. Kalagov, M. V. Kompaniets, M. Yu. Nalimov · 1 citation
Physics and Astronomy · #cond-mat.stat-mech
paper · pdf · doi:10.1016/j.nuclphysb.2016.02.004
arxiv created 2015/05/27 · arxiv updated 2016/03/23
We have studied a Fermi system with attractive U(r)-symmetric interaction at the finite temperatures by the quantum field renormalization group (RG) method. The RG functions have been calculated in the framework of dimensional regularization and minimal subtraction scheme up to five loops. It has been found that for r≥ 4 the RG flux leaves the system's stability region -- the system undergoes a first order phase transition. To estimate the temperature of the transition to superconducting or superfluid phase the RG analysis for composite operators has been performed using three-loops approximation. As the result this analysis shows that for 3D systems estimated phase transition temperature is higher then well known theoretical estimations based on continuous phase transition formalism.