Wormholes, Time Machines, and the Weak Energy Condition

Morris, Michael S.; Thorne, Kip S.; Yurtsever, Ulvi

doi:10.1103/physrevlett.61.1446

Cited by 1,646 publications

(1,764 citation statements)

References 12 publications

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“…But, even if such terms prevent pathologies, by repackaging all of the higher-derivative terms on one side of the field equations and the Einstein tensor on the other, we obtain an "effective" stress-energy which violates the NEC. This means that a variety of exotic solutions to Einstein's equations which require NEC-violating matter could potentially be permitted [37,38,39,40,45,46,47,48], but this must be checked on a case-by-case basis. It would be interesting if we were forced to accept the possibility of exotic solutions of Einstein's equations, or modifications to gravity, from observations that the universe is currently accelerating.…”

Section: Resultsmentioning

confidence: 99%

“…There are some rigorous formulations of this belief, where NEC violation is shown to lead to superluminal propagation, instabilities, and violations of unitarity or causality [30,31,32,33,34,35,36]. Certainly the NEC forbids a number of solutions to Einstein's equations with strange properties: traversable wormholes [37,38], superluminal "warp drives" [39,40,41,42,43,44], time machines [45,46], universes with big rip singularities [47,48], and pathologies with gravitational thermodynamics [49,50,51,52,53] are possible with NECviolating "exotic" matter. 2 (If one considers non-Einstein gravity, these conclusions may differ: for example, the NEC can be violated by a scalar field in Brans-Dicke gravity in Jordan frame [54] without allowing wormholes [55]).…”

Section: Introductionmentioning

confidence: 99%

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Oxidised cosmic acceleration

Wesley

2009

J. Cosmol. Astropart. Phys.

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Abstract:We give detailed proofs of several new no-go theorems for constructing flat fourdimensional accelerating universes from warped dimensional reduction. These new theorems improve upon previous ones by weakening the energy conditions, by including time-dependent compactifications, and by treating accelerated expansion that is not precisely de Sitter. We show that de Sitter expansion violates the higher-dimensional null energy condition (NEC) if the compactification manifold M is one-dimensional, if its intrinsic Ricci scalarR vanishes everywhere, or ifR and the warp function satisfy a simple limit condition. If expansion is not de Sitter, we establish threshold equation-of-state parameters w below which accelerated expansion must be transient. Below the threshold w there are bounds on the number of e-foldings of expansion. If M is one-dimensional orR everywhere vanishing, exceeding the bound implies the NEC is violated. IfR does not vanish everywhere on M, exceeding the bound implies the strong energy condition (SEC) is violated. Observationally, the w thresholds indicate that experiments with finite resolution in w can cleanly discriminate between different models which satisfy or violate the relevant energy conditions.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Oxidised cosmic acceleration

Wesley

2009

J. Cosmol. Astropart. Phys.

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“…Those surviving primordial black holes may be part of the dark matter in our universe. It has not escaped the author's notice that equations (4) and (6) also suggest the information exchange with a black hole [16] may not be strictly forbidden, in principle, by modulating HBC.…”

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confidence: 99%

Control of black hole evaporation?

Ahn

2007

J. High Energy Phys.

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Contradiction between Hawking's semi-classical arguments and string theory on the evaporation of black hole has been one of the most intriguing problems.Previously, a final-state boundary condition inside the black hole was proposed by Horowitz and Maldacena to resolve this contradiction. We point out that original Hawking effect can be regarded as a separate boundary condition at the event horizon for this scenario. Here, we found that the change of Hawking boundary condition may affect the information transfer from the initial collapsing matter to the outgoing Hawking radiation during the evaporation process and as a result the evaporation process itself, significantly.

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“…Only variations of p µ and X µ are allowed to be performed. The resulting equations of motion in flat spacetime arė π µ = eF µ νẊ ν + e ∂ µ V − ∂A µ ∂τ , (1.47) 48) where F µν = ∂ µ A ν − ∂ ν A µ is the electromagnetic field tensor. All components p µ and π µ are independent.…”

Section: The Landscape Of Theoretical Physics: a Global Viewmentioning

confidence: 99%

“…Our aim is not only to describe how a charged particle moves in an electromagnetic field, but also include a particle' s(classical) spin. Therefore, following Pezzaglia [23], we define the momentum polyvector P as the vector momentum p plus the bivector spin angular momentum S, 48) or in components…”

Section: Polyvector Fieldsmentioning

confidence: 99%

The Landscape of Theoretical Physics: A Global View

Pavšič¹

2002

Fundamental Theories of Physics

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This is a book for those who would like to learn something about special and general relativity beyond the usual textbooks, about quantum field theory, the elegant Fock-Schwinger-Stueckelberg proper time formalism, the elegant description of geometry by means of Clifford algebra, about the fascinating possibilities the latter algebra offers in reformulating the existing physical theories, and quantizing them in a natural way. It is shown how Clifford algebra provides much more: it provides room for new physics, with the prospects of resolving certain long standing puzzles. The theory of branes and the idea of how a 3-brane might represent our world is discussed in detail. Much attention is paid to the elegant geometric theory of branes which employs the infinite dimensional space of functions describing branes. Clifford algebra is generalized to the infinite dimensional spaces. In short, this is a book for anybody who would like to explore how the "theory of everything" might possibly be formulated. The theory that would describe all the known phenomena, could not be formulated without taking into account "all" the theoretical tools which are available. Foundations of those tools and their functional interrelations are described in the book. Note: This book was published by Kluwer Academic Publishers in 2001.The body of the posted version is identical to the published one, except for corrections of misprints, and some minor revisions that I have found necessary.

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Wormholes, Time Machines, and the Weak Energy Condition

Cited by 1,646 publications

References 12 publications

Oxidised cosmic acceleration

Oxidised cosmic acceleration

Control of black hole evaporation?

The Landscape of Theoretical Physics: A Global View

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