Semiclassical cosmic string evaporation

TL;DR

This paper introduces a novel tunneling solution describing cosmic string decay into gravitational waves, highlighting how quantum effects can eliminate classical singularities.

Contribution

It presents a new instanton solution for cosmic string decay, showing singularity removal in quantum gravity without black hole formation.

Findings

Derived an analytic continuation of the Kerr metric for the tunneling process

Computed the tunneling rate for cosmic string decay

Demonstrated singularity disappearance in the quantum decay process

Abstract

We describe a new tunneling solution for the decay of a cosmic string into a burst of gravitational waves. We find the relevant instanton and compute the tunneling rate. Locally, our solution is just an analytic continuation of the Kerr metric (but there is no black hole in our solution). An interesting feature of our result is that there is a conical singularity in the initial state but there is no singularity in the final state. This demonstrates that singularities can disappear in quantum gravity in ways that are impossible in classical gravity.