Critical dynamics of the superfluid phase transition: Multiloop calculation of the microscopic model

Results and method of a three-loop renormalization-group calculation in the model of a Bose gas with a local density-density interaction in the formalism of time-dependent Green functions at finite temperature are presented. The results provide support to the recent conjecture [J. Honkonen, M. V. Komarova, Y. G. Molotkov, Nalimov, and J. Honkonen, Theor. Math. Phys. 200, 1237 (2019)] that the dynamics of the superfluid phase transition is described by a model which belongs to the same universality class as the stochastic model A.