Interacting Scalar Fields in the Context of Effective Quantum Gravity

TL;DR

This paper investigates how quantum gravitational interactions influence scalar field theories, showing that gravity can induce asymptotic freedom and potentially resolve triviality issues at high energies.

Contribution

It provides a one-loop analysis of scalar fields coupled to quantum gravity, revealing gravitational corrections that promote asymptotic freedom and fixed point behavior.

Findings

Gravitational corrections lead to asymptotic freedom in scalar theories.

Unique one-loop beta functions for scalar couplings are derived.

Asymptotically free Halpern-Huang potentials are found under certain conditions.

Abstract

A four dimensional scalar field theory with quartic and of higher power interactions suffers the triviality issue at the quantum level. This is due to coupling constants that, contrary to the physical expectations, seem to grow without a bound with energy. Since this problem concerns the high energy domain, interaction with a quantum gravitational field may provide natural solution to it. In this paper we address this problem considering a scalar field theory with a general analytic potential having $\mathbb{Z}_2$ symmetry and interacting with a quantum gravitational field. The dynamics of the latter is governed by the cosmological constant and the Einstein-Hilbert term both being the lowest and next-to-the lowest terms of the effective theory of quantum gravity. Using the Vilkovisky-DeWitt method we calculate the one loop correction to the scalar field effective action. We also derive the unique one loop beta functions for all the scalar field couplings in the MS scheme. We find that the leading gravitational corrections act in the direction of asymptotic freedom. Moreover, assuming for both constants the Newton and the cosmological to have non-zero fixed point values we find asymptotically free Halpern-Huang potentials.