Disorder-induced quantum-Griffiths-like features from a non-conventional renormalization group analysis near four dimensions.

Abstract

We investigate the role played by symmetry conserving quenched disorder on quantum criticality of a variety of d-dimensional systems with a continuous symmetry order parameter.We employ a non standard procedure which combines a preliminary reduction to an effective classical problem and a successive renormalization group treatment. We find a quantum critical point scenario exhibiting unusual features, which remind us of some predictions of the quantum Griffiths phase model