Anomalous criticality near semimetal-to-superfluid quantum phase transition in a two-dimensional Dirac cone model

TL;DR

This paper investigates the quantum critical behavior near the semimetal-to-superfluid transition in a 2D Dirac cone model, revealing anomalous scaling and vanishing quasiparticle properties at the critical point.

Contribution

It provides a detailed renormalization group analysis of the critical point, highlighting anomalous dimensions and the nature of the phase transition in a 2D Dirac system.

Findings

Quasiparticle weight vanishes at criticality

Order parameter correlation length is infinite in the semimetallic phase

Electrons and fluctuations show power-law scaling with anomalous dimensions

Abstract

We analyze the scaling behavior at and near a quantum critical point separating a semimetallic from a superfluid phase. To this end we compute the renormalization group flow for a model of attractively interacting electrons with a linear dispersion around a single Dirac point. We study both ground state and finite temperature properties. In two dimensions, the electrons and the order parameter fluctuations exhibit power-law scaling with anomalous scaling dimensions. The quasi-particle weight and the Fermi velocity vanish at the quantum critical point. The order parameter correlation length turns out to be infinite everywhere in the semimetallic ground state.