BRST Cohomology and Nonlocal Conserved Charges

TL;DR

This paper establishes a connection between nonlocal conserved charges in string theory and BRST cohomology, demonstrating their invariance and symmetry properties in different formalisms.

Contribution

It provides a simple proof that nonlocal conserved charges are BRST-invariant and kappa-symmetric, linking BRST cohomology to conserved charges in superstring theory.

Findings

Nonlocal charges correspond to ghost-number two states in BRST cohomology.

Nonlocal charges are BRST-invariant in the pure spinor formalism.

Nonlocal charges are kappa-symmetric in the Green-Schwarz formalism.

Abstract

A relation is found between nonlocal conserved charges in string theory and certain ghost-number two states in the BRST cohomology. This provides a simple proof that the nonlocal conserved charges for the superstring in an AdS_5 x S^5 background are BRST-invariant in the pure spinor formalism and are kappa-symmetric in the Green-Schwarz formalism.