Solving Einstein’s equation numerically on manifolds with nonorientable spatial slices
Phys. Rev. D 113, 124012 – Published 5 June, 2026
DOI: https://doi.org/10.1103/khyb-qgkt
Abstract
This paper presents solutions to Einstein’s equation, and the numerical methods used to construct them, that describe simple cosmological models on manifolds with compact nonorientable spatial slices. These solutions have been constructed on a selection of manifolds having positive, negative, and vanishing spatial scalar curvatures. One example is shown to be indistinguishable locally from a homogeneous Friedman cosmological model, and others are constructed with significant inhomogeneities. Together, these examples are used to explore the strengths and limitations of the numerical methods used in this study, and to test the code used to implement them.
