Volume independence of large-N QCD with adjoint fermions

TL;DR

This paper investigates whether large-N QCD with adjoint fermions maintains volume independence by analyzing the phase diagram and center-symmetry behavior across different parameters and color numbers.

Contribution

It provides evidence that the unbroken center-symmetry region includes both light and heavy quarks, supporting volume independence in the large-N limit.

Findings

Center-symmetry remains unbroken in certain parameter regions.

The unbroken symmetry region likely extends to the continuum limit.

Results are consistent across N=8 to 15 colors.

Abstract

It has been proposed that four-dimensional QCD with fermions in the adjoint representation exhibits volume-independence in the large-N limit. If correct, this would mean that results for physical quantities could be obtained from the single-site version of the model. A necessary condition for volume-independence is that the (Z_N)^4 center-symmetry of the single-site theory is unbroken. We explore the phase diagram of the theory with a single Dirac fermion using Wilson fermions for a number of colors in the range N=8-15, and identify the region in the parameter space of quark mass and gauge coupling where the symmetry appears to be unbroken. Our evidence suggests that this region includes both light and heavy quarks, and our results are consistent with this region extending to the continuum limit.