The Axion-Instanton Weak Gravity Conjecture and Scalar Fields

TL;DR

This paper extends the Weak Gravity Conjecture to include scalar fields and axion-instanton pairs, providing evidence from Type IIA supergravity to support the modified bounds in quantum gravity theories.

Contribution

It proposes a new extension of the Weak Gravity Conjecture incorporating scalar interactions for axion-instanton systems, supported by supergravity evidence.

Findings

Extended the Weak Gravity Conjecture to scalar fields and axion-instanton pairs.

Provided evidence from Type IIA supergravity supporting the conjecture.

Suggested implications for quantum gravity consistency conditions.

Abstract

We study the Weak Gravity Conjecture in the presence of scalar fields. The Weak Gravity Conjecture is a consistency condition for a theory of quantum gravity asserting that for a U(1) gauge field, there is a particle charged under this field whose mass is bounded by its charge. It was extended to a statement about any canonical pair of (p - 1)-dimensional object and p-form coupling to it, in particular to axion-instanton pairs. The gauge-scalar Weak Gravity Conjecture is a modification of this bound that includes scalar interactions. We propose a similar extension to cases where scalar fields are present for the axion-instanton Weak Gravity Conjecture and provide evidence from Type IIA supergravity.