Classical BRST charge and observables in reducible gauge theories

TL;DR

This paper develops a systematic method for constructing the classical BRST charge and observables in reducible gauge theories, providing explicit formulas and an iterative approach in extended phase space.

Contribution

It introduces a new coordinate system and an explicit iterative method for constructing the BRST charge and observables in reducible gauge theories.

Findings

Explicit expression for the Koszul-Tate differential operator

Simple iterative method for BRST charge construction

Formula for classical BRST observables

Abstract

We study the construction of the classical Becchi-Rouet-Stora-Tyutin (BRST) charge and observables for arbitrary reducible gauge theory. Using a special coordinate system in the extended phase space, we obtain an explicit expression for the Koszul-Tate differential operator and show that the BRST charge can be found by a simple iterative method. We also give a formula for the classical BRST observables.