Time Machines and AdS Solitons with Negative Mass

TL;DR

This paper explores negative mass solutions in odd-dimensional AdS spacetimes, revealing smooth time machines and static solitons, and constructs specific time machine solutions in five-dimensional supergravity with magnetic charges.

Contribution

It demonstrates the existence of smooth negative mass time machines and AdS solitons in odd dimensions, and constructs explicit solutions in five-dimensional supergravity.

Findings

Negative mass time machines are smooth with no singularities.

Static AdS solitons with negative mass can be obtained by tuning angular momenta.

Constructed five-dimensional supergravity time machines with magnetic dipole charges.

Abstract

We show that in D=2n+1 dimensions, when mass is negative and all angular momenta are non-vanishing, Kerr and Kerr-AdS metrics describe smooth time machines, with no curvature singularity. Turning off the angular momenta appropriately can lead to static AdS solitons with negative mass. Setting zero the cosmological constant yields a class of Ricci-flat K\"ahler metrics in D=2n dimensions. We also show that Euclidean-signatured AdS solitons with negative mass can also arise in odd dimensions. We then construct time machines in D=5 minimal gauged supergravity that carry only magnetic dipole charges. Turning off the cosmological constant, the time machine becomes massless and asymptotically flat. It can be described as a constant time bundle over the Eguchi-Hanson instanton.