# Gross-Neveu-Yukawa model at three loops and Ising critical behavior of Dirac systems

## TL;DR

This paper advances the understanding of quantum critical behavior in Dirac systems by calculating three-loop critical exponents of the Gross-Neveu-Yukawa model in $4- ext{epsilon}$ dimensions, with applications to various condensed matter phase transitions.

## Contribution

It provides the first three-loop calculations of critical exponents for the Gross-Neveu-Yukawa theory, extending previous two-loop results and applying them to real physical phase transitions.

## Key findings

- Critical exponents computed at three loops agree with known two-loop results.
- Emergent super-scaling relations hold up to three loops in single-component fermion limit.
- Padé approximants of series provide insights into phase transition behaviors.

## Abstract

Dirac and Weyl fermions appear as quasi-particle excitations in many different condensed-matter systems. They display various quantum transitions which represent unconventional universality classes related to the variants of the Gross-Neveu model. In this work we study the bosonized version of the standard Gross-Neveu model -- the Gross-Neveu-Yukawa theory -- at three-loop order, and compute critical exponents in $4-\epsilon$ dimensions for general number of fermion flavors. Our results fully encompass the previously known two-loop calculations, and agree with the known three-loop results in the purely bosonic limit of the theory. We also find the exponents to satisfy the emergent super-scaling relations in the limit of a single-component fermion, order by order up to three loops. Finally, we apply the computed series for the exponents and their Pad\'e approximants to several phase transitions of current interest: metal-insulator transitions of spin-1/2 and spinless fermions on the honeycomb lattice, emergent supersymmetric surface field theory in topological phases, as well as the disorder-induced quantum transition in Weyl semimetals. Comparison with the results of other analytical and numerical methods is discussed.