From wormhole to time machine: Remarks on Hawking's chronology protection conjecture
- Physics Department, Washington University, St. Louis, Missouri 63130-4899 (United States)
The recent interest in time machines'' has been largely fueled by the [ital apparent] ease with which such systems may be formed in general relativity, given relatively benign initial conditions such as the existence of traversable wormholes or of infinite cosmic strings. This rather disturbing state of affairs has led Hawking to formulate his [ital chronology] [ital protection] [ital conjecture], whereby the formation of time machines'' is forbidden. This paper will use several simple examples to argue that the Universe appears to exhibit a defense in depth'' strategy in this regard. For appropriate parameter regimes, Casimir effects, wormhole disruption effects, and gravitational back reaction effects all contribute to the fight against time travel. Particular attention is paid to the role of the quantum gravity cutoff. For the class of model problems considered it is shown that the gravitational back reaction becomes large before the Planck scale quantum gravity cutoff is reached, thus supporting Hawking's conjecture.
- OSTI ID:
- 6899227
- Journal Information:
- Physical Review, D (Particles Fields); (United States), Vol. 47:2; ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
UNIVERSE
QUANTUM GRAVITY
CASIMIR EFFECT
COSMOLOGY
GENERAL RELATIVITY THEORY
GEODESICS
GRAVITATIONAL FIELDS
RENORMALIZATION
SEMICLASSICAL APPROXIMATION
SPACE-TIME
STRING MODELS
TIME DEPENDENCE
VACUUM POLARIZATION
COMPOSITE MODELS
EXTENDED PARTICLE MODEL
FIELD THEORIES
MATHEMATICAL MODELS
PARTICLE MODELS
QUANTUM FIELD THEORY
QUARK MODEL
662100* - General Theory of Particles & Fields- (1992-)