JHEP 1807 (2018) 088 arXiv link
BPS Kerr-AdS time machines
M. Cvetič1,2, Wei-Jian Geng1, H. Lü3∗, C. N. Pope1,4,5
1. Department of Physics, Beijing Normal University, Beijing 100875, China
2. Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
3. Department of Physics, Tianjin University, Tianjin 300350, China
4. George P. & Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA
5. DAMTP, Centre for Mathematical Sciences, Cambridge University, Wilberforce Road, Cambridge CB3 OWA, UK
∗ Corresponding Authors: mrhonglu@gmail.com
Abstract:
It was recently observed that Kerr-AdS metrics with negative mass can describe smooth spacetimes that have a region within which naked closed time-like curves can arise, bounded by a velocity of light surface. Such spacetimes are sometimes known as time machines. In this paper we study the BPS limit of these metrics, and find that the mass and angular momenta become discretised. The completeness of the spacetime also requires that the asymptotic time coordinate be periodic, with precisely the same period as that which arises naturally for the global AdS, viewed as a hyperboliod in one extra dimension, in which the time machine spacetime is immersed. For the case of equal angular momenta in odd dimensions, we construct the Killing spinors explicitly, and show they are consistent with the global structure. Thus in examples where the solutions can be embedded in gauged supergravity, they will be supersymmetric. We also compare the global structure of the BPS AdS3 time machine with the BTZ black hole, and show that the global structure allows two different supersymmetric limits.
