Renormalization Group in Non-Relativistic Quantum Statistics

¹ Department of Military Technology, National Defence University, Santahaminantie 2, 00860 Helsinki, Finland
² Department of Theoretical Physics, Faculty of Physics, Saint Petersburg State University, Ul’yanovskaya 1, Petrodvorets, 198504 Saint Petersburg, Russia

^★ e-mail: juha.honkonen@helsinki.fi

Published online: 20 January 2020

Abstract

Dynamic behaviour of a boson gas near the condensation transition in the symmetric phase is analyzed with the use of an effective large-scale model derived from time-dependent Green functions at finite temperature. A renormalization-group analysis shows that the scaling exponents of critical dynamics of the effective multi-charge model coincide with those of the standard model A. The departure of this result from the description of the superfluid transition by either model E or F of the standard phenomenological stochastic models is corroborated by the analysis of a generalization of model F, which takes into account the effect of compressible fluid velocity. It is also shown that, contrary to the single-charge model A, there are several correction exponents in the effective model, which are calculated at the leading order of the ɛ= 4 − d expansion.