1997/02/21 by Matt Visser · 1 voice · 4 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Noncommutative and Quantum Gravity Theories #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.55.5212
published as Phys.Rev. D55 (1997) 5212-5214 · 4 pages; ReV_TeX 3.0 in twocolumn mode; two line drawings using the LaTeX picture environment; Accepted for publication in Physical Review D15
arxiv created 1997/02/21 · arxiv published 1997/02/21 · openalex publication_date 1997/04/15 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this brief report I introduce a yet another class of geometries for which semi-classical chronology protection theorems are of dubious physical reliability. I consider a ``Roman ring'' of traversable wormholes, wherein a number of wormholes are arranged in a ring in such a manner that no subset of wormholes is near to chronology violation, though the combined system can be arbitrarily close to chronology violation. I show that (with enough wormholes in the ring) the gravitational vacuum polarization (the expectation value of the quantum stress-energy tensor) can be made arbitrarily small. In particular the back-reaction can be kept arbitrarily small all the way to the ``reliability horizon''---so that semi-classical quantum gravity becomes unreliable before the gravitational back reaction becomes large.