Ghost sector and geometry in minimal Landau gauge: Further constraining the infinite-volume limit

Author(s)

Cucchieri, Attilio ^[1] ; Mendes, Tereza ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13560970 Sao Paulo - Brazil

• Document type: Journal article
• Source: Physical Review D; v. 88, n. 11 DEC 3 2013.
• Web of Science Citations: 11

Abstract

We present improved upper and lower bounds for the momentum-space ghost propagator of Yang-Mills theories in terms of the two smallest nonzero eigenvalues (and their corresponding eigenvectors) of the Faddeev-Popov matrix. These results are verified using data from four-dimensional numerical simulations of SU(2) lattice gauge theory in minimal Landau gauge at beta = 2.2, for lattice sides N = 16, 32, 48 and 64. Gribov-copy effects are discussed by considering four different sets of numerical minima. We then present a lower bound for the smallest nonzero eigenvalue of the Faddeev-Popov matrix in terms of the smallest nonzero momentum on the lattice and of a parameter characterizing the geometry of the first Gribov region Omega. This allows a simple and intuitive description of the infinite-volume limit in the ghost sector. In particular, we show how nonperturbative effects may be quantified by the rate at which typical thermalized and gauge-fixed configurations approach the boundary of Omega, known as the first Gribov horizon. As a result, a simple and concrete explanation emerges for why lattice studies do not observe an enhanced ghost propagator in the deep infrared limit. Most of the simulations have been performed on the Blue Gene/P-IBM supercomputer shared by Rice University and Sao Paulo University. (AU)

• FAPESP's process: 09/50180-0 - Study of hadronic interactions at high energies
• Grantee: Yogiro Hama
• Support Opportunities: Research Projects - Thematic Grants