English

The strong CP problem, general covariance, and horizons

High Energy Physics - Theory 2021-11-17 v3 General Relativity and Quantum Cosmology High Energy Physics - Phenomenology

Abstract

We discuss the strong CP problem in the context of quantum field theory in the presence of horizons. We argue that general covariance places constraints on the topological structure of the theory. In particular, as in QCD, it means that different topological sectors of the theory can only sum incoherently, because the degrees of freedom beyond the horizon must be traced over for general covariance to apply. This might lead to a solution of the so-called strong CP problem without extra observable dynamics.

Keywords

Cite

@article{arxiv.2007.13183,
  title  = {The strong CP problem, general covariance, and horizons},
  author = {Giorgio Torrieri and Henrique Dias Truran},
  journal= {arXiv preprint arXiv:2007.13183},
  year   = {2021}
}

Comments

Accepted for publication, Classical and Quantum Gravity

R2 v1 2026-06-23T17:24:49.906Z