The Lattice Free Energy with Overlap Fermions: A Two-Loop Result

TL;DR

This paper computes the two-loop partition function of lattice QCD with overlap fermions, providing key results like free energy and plaquette, and establishing a foundation for future higher-loop calculations in this formalism.

Contribution

It presents the first two-loop calculation of the lattice QCD partition function using overlap fermions, including explicit dependence on parameters and serving as a prototype for advanced computations.

Findings

Two-loop free energy and plaquette calculated.

Results depend explicitly on parameters like $M_0$, $N$, and $N_f$.

Method serves as a prototype for higher-loop calculations.

Abstract

We calculate the 2-loop partition function of QCD on the lattice, using the Wilson formulation for gluons and the overlap-Dirac operator for fermions. Direct by-products of our result are the 2-loop free energy and average plaquette. Our calculation serves also as a prototype for further higher loop calculations in the overlap formalism. We present our results as a function of a free parameter $M_0$ entering the overlap action; the dependence on the number of colors $N$ and fermionic flavors $N_f$ is shown explicitly.