$ε$-Expansion in the Gross-Neveu Model from Conformal Field Theory
Sudip Ghosh, Rajesh Kumar Gupta, Kasi Jaswin, Amin A. Nizami
TL;DR
The paper applies conformal-field-theory methods to the Gross-Neveu model near $d=2$ to compute leading-order anomalous dimensions of fermionic composites without Feynman diagrams. By matching two- and three-point functions at the UV fixed point and employing multiplet recombination, the authors derive recursion relations for the leading $\epsilon$-dependent anomalous dimensions and obtain explicit formulas for both basic fermion/fermion-scalar operators and higher composites. They also determine the anomalous dimension of a non-singlet scalar primary, finding new leading-order data. These results validate perturbative expectations for fermions and demonstrate a diagram-free approach that can be extended with bootstrap techniques to higher orders and more general operators.
Abstract
We compute the anomalous dimensions of a class of operators of the form $(\barψψ)^p$ and $(\barψψ)^pψ$ to leading order in $ε$ in the Gross-Neveu model in $2+ε$ dimensions. We use the techniques developed in arXiv: 1505.00963.
