Massive Dirac fermions from holography

TL;DR

This paper develops a holographic framework to study massive Dirac fermions, revealing how Yukawa interactions induce spectral gaps and phase transitions, including topological and quantum critical points, with implications for condensed matter systems.

Contribution

It introduces a novel holographic approach with coupled bulk fermions and explores semiholographic extensions, uncovering new spectral and phase transition phenomena.

Findings

Yukawa coupling induces a gap in the holographic fermionic spectrum.

Semiholography reveals a quantum critical point and topological phase transition.

Doping causes a quantum phase transition between gapped and Fermi liquid states.

Abstract

We provide a framework to compute the dynamics of massive Dirac fermions using holography. To this end we consider two bulk Dirac fermions that are coupled via a Yukawa interaction and propagate on a gravitational background in which a mass deformation is introduced. Moreover, we discuss the incorporation of this approach in semiholography. The resulting undoped fermionic spectral functions indeed show that the Yukawa coupling induces a gap in the holographic spectrum, whereas the semiholographic extension is in general gapped but additionally contains a quantum critical point at which the effective fermion mass vanishes and a topological phase transition occurs. Furthermore, when introducing doping, the fermionic spectral functions show a quantum phase transition between a gapped material and a Fermi liquid.