One-Loop Divergences in 6D Conformal Gravity

TL;DR

This paper investigates one-loop divergences in six-dimensional conformal gravity using the Exact Renormalization Group Equation, analyzing divergences on various Einstein space backgrounds to understand conformal invariants and test the method's effectiveness.

Contribution

It applies the Exact Renormalization Group Equation approach to 6D conformal gravity, providing new insights into divergences and conformal invariants on multiple backgrounds.

Findings

Calculated power-law and logarithmic divergences.

Extracted coefficients for Euler density and conformal invariants.

Confirmed the method's validity by reexamining 4D conformal gravity.

Abstract

Using Exact Renormalization Group Equation approach and background field method, we investigate the one-loop problem in a six-dimensional conformal gravity theory whose Lagrangian takes the same form as holographic Weyl anomaly of multiple coincident M5-branes. We choose the backgrounds to be the symmetric Einstein spaces including S6, CP3, S2 \times S4, S2 \times CP2, S3 \times S3 and S2 \times S2 \times S2. Evaluating the functional sums gives power-law and logarithmic divergences. We extract from the specific values of logarithmic divergence on above backgrounds, the coefficient in front of Euler density and two linear equations constraining the coefficients in front of three type-B conformal invariants. As a test of the effectiveness of Exact Renormalization Group Equation approach to quantum conformal gravity, we reexaminethe one-loop problem in four-dimensional conformal gravity and confirm the logarithmic divergence derived from generalized Schwinger-DeWitt method.