Local Boundary Conditions in Quantum Supergravity

TL;DR

This paper investigates local boundary conditions in quantum supergravity on manifolds with boundary, demonstrating their effects on one-loop finiteness and the role of boundary data in the spectral analysis.

Contribution

It introduces and analyzes local boundary conditions for gravitino perturbations in quantum supergravity, showing their impact on one-loop finiteness and spectral properties.

Findings

Transverse-traceless perturbations' contribution to ζ(0) vanishes with zero boundary data.

One-loop finiteness requires two boundary 3-surfaces and no exact gauge-ghost cancellation.

Pure gravity is one-loop finite under covariant gauge-averaging with these boundary conditions.

Abstract

When quantum supergravity is studied on manifolds with boundary, one may consider local boundary conditions which fix on the initial surface the whole primed part of tangential components of gravitino perturbations, and fix on the final surface the whole unprimed part of tangential components of gravitino perturbations. This paper studies such local boundary conditions in a flat Euclidean background bounded by two concentric 3-spheres. It is shown that, as far as transverse-traceless perturbations are concerned, the resulting contribution to $\zeta(0)$ vanishes when such boundary data are set to zero, exactly as in the case when non-local boundary conditions of the spectral type are imposed. These properties may be used to show that one-loop finiteness of massless supergravity models is only achieved when two boundary 3-surfaces occur, and there is no exact cancellation of the contributions of gauge and ghost modes in the Faddeev-Popov path integral. In these particular cases, which rely on the use of covariant gauge-averaging functionals, pure gravity is one-loop finite as well.