Gravitational domain walls and the dynamics of the gravitational constant G

Gravitational domain walls and the dynamics of the gravitational constant G From the point of view of elementary particle physics, the gravitational constant G is extraordinarily small. This has led to asking whether it could have decayed to its present value from an initial one commensurate with microscopical units. A mechanism that leads to such a decay is proposed herein. It is based on assuming that G may take different values within regions of the universe separated by a novel kind of domain wall, a “G-wall.” The idea is implemented by introducing a gauge potential Aμνρ, and its conjugate D, which determines the value of G as an integration constant rather than a fundamental constant. The value of G jumps when one goes through a G-wall. The procedure extends one previously developed for the cosmological constant, but the generalization is far from straightforward: (i) The intrinsic geometry of a G-wall is not the same as seen from its two sides because the second law of black hole thermodynamics mandates that the jump in G must cause a discontinuity in the scale of length. (ii) The size of the decay step in G is controlled by a function G(D) which may be chosen so as to diminish the value of G towards the asymptote G=0. It is shown that: (i) The dynamics of the gravitational field with G treated as a dynamical variable, coupled to G-walls and matter, follows from an action principle, which is given. (ii) A particle that impinges on a G-wall may be refracted or reflected. (iii) The various forces between two particles change when a G-wall is inserted in between them. (iv) G-walls may be nucleated trough tunneling and thermal effects, whose semiclassical probabilities are evaluated. (v) If the action principle is constructed properly, the entropy of a black hole increases when the value of the gravitational constant is changed through the absorption of a G-wall by the hole. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Physical Review D American Physical Society (APS)

Gravitational domain walls and the dynamics of the gravitational constant G

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Gravitational domain walls and the dynamics of the gravitational constant G

Abstract

From the point of view of elementary particle physics, the gravitational constant G is extraordinarily small. This has led to asking whether it could have decayed to its present value from an initial one commensurate with microscopical units. A mechanism that leads to such a decay is proposed herein. It is based on assuming that G may take different values within regions of the universe separated by a novel kind of domain wall, a “G-wall.” The idea is implemented by introducing a gauge potential Aμνρ, and its conjugate D, which determines the value of G as an integration constant rather than a fundamental constant. The value of G jumps when one goes through a G-wall. The procedure extends one previously developed for the cosmological constant, but the generalization is far from straightforward: (i) The intrinsic geometry of a G-wall is not the same as seen from its two sides because the second law of black hole thermodynamics mandates that the jump in G must cause a discontinuity in the scale of length. (ii) The size of the decay step in G is controlled by a function G(D) which may be chosen so as to diminish the value of G towards the asymptote G=0. It is shown that: (i) The dynamics of the gravitational field with G treated as a dynamical variable, coupled to G-walls and matter, follows from an action principle, which is given. (ii) A particle that impinges on a G-wall may be refracted or reflected. (iii) The various forces between two particles change when a G-wall is inserted in between them. (iv) G-walls may be nucleated trough tunneling and thermal effects, whose semiclassical probabilities are evaluated. (v) If the action principle is constructed properly, the entropy of a black hole increases when the value of the gravitational constant is changed through the absorption of a G-wall by the hole.
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Publisher
American Physical Society (APS)
Copyright
Copyright © © 2017 American Physical Society
ISSN
1550-7998
eISSN
1550-2368
D.O.I.
10.1103/PhysRevD.96.025013
Publisher site
See Article on Publisher Site

Abstract

From the point of view of elementary particle physics, the gravitational constant G is extraordinarily small. This has led to asking whether it could have decayed to its present value from an initial one commensurate with microscopical units. A mechanism that leads to such a decay is proposed herein. It is based on assuming that G may take different values within regions of the universe separated by a novel kind of domain wall, a “G-wall.” The idea is implemented by introducing a gauge potential Aμνρ, and its conjugate D, which determines the value of G as an integration constant rather than a fundamental constant. The value of G jumps when one goes through a G-wall. The procedure extends one previously developed for the cosmological constant, but the generalization is far from straightforward: (i) The intrinsic geometry of a G-wall is not the same as seen from its two sides because the second law of black hole thermodynamics mandates that the jump in G must cause a discontinuity in the scale of length. (ii) The size of the decay step in G is controlled by a function G(D) which may be chosen so as to diminish the value of G towards the asymptote G=0. It is shown that: (i) The dynamics of the gravitational field with G treated as a dynamical variable, coupled to G-walls and matter, follows from an action principle, which is given. (ii) A particle that impinges on a G-wall may be refracted or reflected. (iii) The various forces between two particles change when a G-wall is inserted in between them. (iv) G-walls may be nucleated trough tunneling and thermal effects, whose semiclassical probabilities are evaluated. (v) If the action principle is constructed properly, the entropy of a black hole increases when the value of the gravitational constant is changed through the absorption of a G-wall by the hole.

Journal

Physical Review DAmerican Physical Society (APS)

Published: Jul 15, 2017

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