Non-perturbative renormalization group approach to zero-temperature Bose systems

Abstract

We use a non-perturbative renormalization group technique to study interacting bosons at zero temperature. Our approach reveals the instability of the Bogoliubov fixed point when d≤3 and yields the exact infrared behavior in all dimensions d>1 within a rather simple theoretical framework. It also enables to compute the low-energy properties in terms of the parameters of a microscopic model. In one dimension and for not too strong interactions, it yields a good picture of the Luttinger-liquid behavior of the superfluid phase.