Chern-Simons gravity and PT Symmetry
Abstract
This paper considers the possibility that, starting from a relativistic Hermitian quantum field theory in the ultraviolet (UV) regime, and applying a non-perturbative renormalization-group (RG) flow, we arrive at a situation where there are infrared (IR) singularities in the RG flow of couplings. The latter can be resolved by assuming that the theory can have a phase described by a related non-Hermitian PT-symmetric modification in the IR. The UV-to-IR (Hermitian-to-PT-symmetric) transition can occur in a single renormalization-group flow of the pertinent couplings, as demonstrated in concrete examples. When embedded in a gravitational setting such a transition can lead to a repulsive gravity phase. If there is a RG flow to a repulsive PT -symmetric gravity, then this would be an alternative to dark energy. The discussion here is presented in the context of a string-inspired Chern-Simons gravitational effective action, which involves a pseudoscalar (axion-like) field coupled to Abelian gauge fields and gravity; it may also hold more generally in gravity with torsion. The validity of such a scenario in realistic theories might alleviate the need for de Sitter phases in the current epoch of cosmological evolution, thus avoiding their associated conceptual and technical complications.
Cite
@article{arxiv.2402.14513,
title = {Chern-Simons gravity and PT Symmetry},
author = {Nick E. Mavromatos and Sarben Sarkar},
journal= {arXiv preprint arXiv:2402.14513},
year = {2024}
}
Comments
20 pages, revtex, 2 figures incorporated. Amended version accepted for publication in Physical Review D. Augmented abstract, modified structure in introduction (subsections A and B for better guidance of the reader), better links between various sections. Addition on potential phenomenological tests in the final part of conclusions section. References added. No effects on conclusions