Remarks on the Taub-NUT solution in Chern-Simons modified gravity

TL;DR

This paper explores the extension of NUT spacetimes within Einstein--Chern-Simons gravity, revealing that while they resemble GR solutions asymptotically, they exhibit unbounded curvature inside the horizon.

Contribution

It provides the first analytical and numerical analysis of NUT solutions in dynamical Einstein--Chern-Simons gravity, highlighting their similarities and differences with GR counterparts.

Findings

Solutions approach asymptotic NUT spacetime in ECS theory.

Inside the horizon, curvature grows without bound in ECS solutions.

ECS configurations retain basic properties of GR NUT spacetimes.

Abstract

We discuss the generalization of the NUT spacetime in General Relativity (GR) within the framework of the (dynamical) Einstein--Chern-Simons (ECS) theory with a massless scalar field. These configurations approach asymptotically the NUT spacetime and are characterized by the `electric' and `magnetic' mass parameters and a scalar `charge'. The solutions are found both analytically and numerically. The analytical approach is perturbative around the Einstein gravity background. Our results indicate that the ECS configurations share all basic properties of the NUT spacetime in GR. However, when considering the solutions inside the event horizon, we find that in contrast to the GR case, the spacetime curvature grows (apparently) without bound.