1/N-expansion for the critical temperature of the Bose gas

Department for Theoretical Physics, Ivan Franko National University of Lviv - 12 Drahomanov Street, Lviv-5, 79005, Ukraine

^(a) volodyapastukhov@gmail.com

Received: 1 May 2017
Accepted: 11 July 2017

Abstract

We revised the large-N expansion for a three-dimensional Bose system with short-range repulsion in normal phase. Particularly, for the model potential that is characterised only by the s-wave scattering length a the full numerical calculations of the critical temperature in the -approximation as a function of the gas parameter are performed. Additionally to the well-known result in the dilute limit we estimated analytically the leading-order strong-coupling behavior of the Bose-Einstein condensation transition temperature. It is shown that the critical temperature shift of the non-ideal Bose gas grows at small , reaches some maximal value and then falls down becoming negative.