Criticality of n-vector quantum systems is studied, via a renormalization group treatment, assuming a pair interaction which decays as a power law involving a characteristics parameter θ. Within a “single”-expansion parameter scheme for finite values of θ, a novel fixed point appears for...

Within the Wilson Renormalization Group (WRG) approach as applied to d-dimensional quantum systems using appropriate functional representations, we develop a general method for describing the critical behaviour driven by the temperature T when the quantum fluctuations are into play. It consists...

We study the effects of correlated symmetry-breaking-like random fields on critical properties of a d-dimensional sine-Gordon model. A Wilsonian renormalization group analysis shows an unusual scenario in the absence of stable fixed points. The physical nature of the related runaway in the...