Search arXivSearch

arXiv · 2406.15059

Gribov Problem and Stochastic Quantization

Abstract

The standard procedure for quantizing gauge fields is the Faddeev-Popov quantization, which performs gauge fixing in the path integral formulation and introduces additional ghost fields. This approach provides the foundation for calculations in quantum Yang-Mills theory. However, in 1978, Vladimir Gribov showed that the gauge-fixing procedure was incomplete, with residual gauge copies (called Gribov copies) still entering the path integral even after gauge fixing. These copies impact the infrared behavior of the theory and modify gauge-dependent quantities, such as gluon and ghost propagators, as they represent redundant integrations over gauge-equivalent configurations. Furthermore, their existence breaks down the Faddeev-Popov prescription at a fundamental level. To partially resolve this, Gribov proposed restricting the path integral to the Gribov region, which alters the gluon propagator semiclassically in a way that points to gluon confinement in the Yang-Mills theory. In this thesis, we comprehensively study the Gribov problem analytically. After reviewing Faddeev-Popov quantization, the BRST symmetry of the complete Lagrangian and the Gribov problem in depth, we detail Gribov's semi-classical resolution involving restriction of the path integral to the Gribov region, outlining its effects on the theory. Further, we elucidate stochastic quantization prescription for quantizing the gauge fields. This alternate quantization prescription hints towards a formalism devoid of the Gribov problem, making it an interesting candidate for quantizing and studying the non-perturbative regime of gauge theories.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Adithya A Rao. 2024-06-21. Gribov Problem and Stochastic Quantization. https://arxiv.org/abs/2406.15059

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Introduction to Generalized Symmetries

These notes were prepared for a series of intensive lectures delivered at Hokkaido University, Nagoya University, Kyoto University, and Kyushu University. We begin with a brief review of higher-form symmetries, anomalies, and discrete gauge theories, before introducing non-invertible symmetries in $(1+1)$-dimensional systems. The basic structure of fusion categories is then discussed, including a discussion of categorical analogs of discrete gauging and representation theory. We subsequently turn to $(3+1)$-dimensional theories, where several physical applications of non-invertible symmetries are discussed. These notes are intended to be largely self-contained, and require no prior familiarity with subjects such as conformal field theory or lattice models.

hep-th

Planar loop integrands from cuts in $D$ dimensions

We present a direct reconstruction formula for planar loop integrands from $D$-dimensional generalized unitarity cuts in any colored theory. The reconstruction combinatorics is separated from the theory-dependent tree amplitudes entering the cuts: for the $L$-loop $n$-point color-ordered amplitude, the integrand is expressed as a sum over admissible non-scaleless scalar graphs dressed by corresponding cuts in $D$ dimensions; the coefficients are given by the universal Möbius-inversion formula of the refinement poset, or equivalently one minus the Euler characteristics of associated complexes. As an application we write down closed-formulas for loop integrands in pure Yang--Mills theory, where the required cuts are generated by gluing $D$-dimensional tree amplitudes and summing over internal gluon states. We also use the two-loop five-point case as a validation, comparing with known integrand data and after integration-by-parts reduction, with known integrated helicity amplitudes. The same framework also produces compact cut-organized data for larger examples, including the two-loop six-point and three-loop four-point cases. We also describe the corresponding simplification in maximally supersymmetric Yang--Mills theory, where the absence of bubble and triangle subgraphs reduces the relevant cut poset substantially.

hep-th

Free Field Realization of $\mathcal{W}$-Algebra Associated with Exceptional Lie Algebras

We study the free field realization of the $\mathcal{W}$-algebra associated with the exceptional Lie algebras $E_6$, $E_7$, $E_8$, and $F_4$. We develop a recursive construction in which a $\mathcal{W}$-algebra of rank $r$ is obtained from a $\mathcal{W}$-algebra of rank $r-1$ together with a free boson. The $\mathcal{W}$-currents are constructed from the zero commutation relation with the screening charges. The $\mathcal{W}E_6/\mathcal{W}E_7$ algebra is constructed from the $\mathcal{W}D_5/\mathcal{W}D_6$ algebra and is shown to be the same as that realized from the $\mathcal{W}A_5/\mathcal{W}E_6$ algebra, up to a change of the free field basis. The spin-$8$ generator of the $\mathcal{W}E_8$ algebra is built from the $\mathcal{W}D_7$ algebra. The recursive construction of the $\mathcal{W}BC_r$ algebras is also studied. We then realize the $\mathcal{W}F_4$ algebra based on the $\mathcal{W}BC_3$ algebra. Furthermore, the $\mathcal{W}$-charges of the generators of the $\mathcal{W}E_{6,7}$, $\mathcal{W}BC_{2,3}$, and $\mathcal{W}F_4$ algebras are calculated and expressed in terms of the Casimir invariants.

hep-th