General parametrization of wormhole spacetimes and its application to shadows and quasinormal modes

TL;DR

This paper introduces a comprehensive parametrization method for spherically symmetric traversable wormholes that accurately models their shadows and quasinormal modes across the entire spacetime, facilitating observational tests.

Contribution

It presents a novel, extended parametrization framework for wormhole spacetimes using continued-fraction expansion, applicable beyond weak fields and including slow rotation effects.

Findings

Parametrization achieves high accuracy with few parameters.

Effective modeling of shadows and quasinormal modes.

Method applicable to various wormhole metrics.

Abstract

The general parametrization for spacetimes of spherically symmetric Lorentzian, traversable wormholes in an arbitrary metric theory of gravity is presented. The parametrization is similar in spirit to the post-Newtonian parametrized formalism, but with validity that extends beyond the weak field region and covers the whole space. Our method is based on a continued-fraction expansion in terms of a compactified radial coordinate. Calculations of shadows and quasinormal modes for various examples of parametrization of known wormhole metrics that we have performed show that, for most cases, the parametrization provides excellent accuracy already at the first order. Therefore, only a few parameters are dominant and important for finding potentially observable quantities in a wormhole background. We have also extended the analysis to the regime of slow rotation.