On divergences in non-minimal N=4 conformal supergravity

TL;DR

This paper investigates the quantum consistency of N=4 conformal supergravity in four dimensions, demonstrating that divergences and anomalies can be canceled by coupling to N=4 super Yang-Mills, regardless of the non-minimal function form.

Contribution

It shows that divergences and anomalies in non-minimal N=4 conformal supergravity are cancelable similarly to the minimal case, independent of the holomorphic function f.

Findings

Divergences and anomalies are independent of the function f.

Coupling to N=4 super Yang-Mills cancels divergences.

Non-minimal and minimal theories share similar cancellation mechanisms.

Abstract

We review the question of quantum consistency of N=4 conformal supergravity in 4 dimensions. The UV divergences and anomalies of the standard ("minimal") conformal supergravity where the complex scalar $\phi$ is not coupled to the Weyl graviton kinetic term can be cancelled by coupling this theory to N=4 super Yang-Mills with gauge group of dimension 4. The same turns out to be true also for the "non-minimal" N=4 conformal supergravity with the action (recently constructed in arXiv:1609.09083) depending on an arbitrary holomorphic function $f(\phi)$. The special case of the "non-minimal" conformal supergravity with $f= e^{2\phi}$ appears in the twistor-string theory. We show that divergences and anomalies do not depend on the form of the function $f$ and thus can be cancelled just as in the "minimal" $f=1$ case by coupling the theory to four N=4 vector multiplets.