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Register a new userWormholes, geometric flows and singularities
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In this paper we study the evolution of wormhole geometries under intrinsic geometric flows. We make evolve numerically the time symmetric foliations of a family of spherically symmetric asymptotically flat wormholes under the Ricci flow and under the RG-2 flow. We use some theorems adapted from the compact case for studying the evolution of different wormhole types, specially those with high curvature zones. Some metrics expand and others contract at the beginning of the flow, however, all metrics pinch-off at certain time. We present a numerical study of the evolution of wormhole singularities in three dimensions extending the theoretical estimations. Finally, we calculate numerically the Hamiltons entropy of the surface and show that it is monotonous through the evolution.
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We analyze analytically and numerically the origin of the singularity in the course of the collapse of a wormhole with the exotic scalar field Psi with negative energy density, and with this field Psi together with the ordered magnetic field H. We do this under the simplifying assumptions of the spherical symmetry and that in the vicinity of the singularity the solution of the Einstein equations depends only on one coordinate (the homogeneous approximation). In the framework of these assumptions we found the principal difference between the case of the collapse of the ordinary scalar field Phi with the positive energy density together with an ordered magnetic field H and the collapse of the exotic scalar field Psi together with the magnetic field H. The later case is important for the possible astrophysical manifestation of the wormholes.
Evidence to the case that classical gravitation provides the clue to make sense out of quantum gravity is presented. The key observation is the existence in classical gravitation of child universe solutions or almost solutions, almost because of some singularity problems. The difficulties of these child universe solutions due to their generic singularity problems will be very likely be cured by quantum effects, just like for example almost instanton solutions are made relevant in gauge theories with breaking of conformal invariance. Some well motivated modifcations of General Relativity where these singularity problems are absent even at the classical level are discussed. High energy density excitations, responsible for UV divergences in quantum field theories, including quantum gravity, are likely to be the source of child universes which carry them out of the original space time. This decoupling could prevent these high UV excitations from having any influence on physical amplitudes. Child universe production could therefore be responsible for UV regularization in quantum field theories which take into account semiclassically gravitational effects. Child universe production in the last stages of black hole evaporation, the prediction of absence of tranplanckian primordial perturbations, connection to the minimum length hypothesis and in particular the connection to the maximal curvature hypothesis are discussed. Some discussion of superexcited states in the case these states are Kaluza Klein excitations is carried out. Finally, the posibility of obtaining string like effects from the wormholes associated with the child universes is discussed.
Wormholes are hypothetical topologically-non-trivial structures of the spacetime. From the theoretical point of view, the possibility of their existence is challenging but cannot be ruled out. This article is a compact and non-exhaustive review of past and current efforts to search for astrophysical wormholes in the Universe.
In this paper we construct a precise mathematical model of the Multiverse, consisted of the universes, that are connected with each other by dynamical wormholes. We consider spherically symmetric free of matter wormholes. At the same time separate universes in this model are not necessary spherically symmetric and can significantly differ from one another. We also analyze a possibility of the information exchange between different universes.
We consider the process of catastrophic expansion of a spacelike wormhole after a violation of its equilibrium state. The dynamics of deformation of the comoving reference frame is investigated. We show that the deformation has a very specific anisotropic feature. The statement made earlier by other authors, that in the process of expanding the wormhole connecting two universes these universes ultimately unite into one universe, is not correct. We show that the transverse size of the wormhole (its throat) increases and the length of the corridor decreases which does not correspond to the de Sitter model.
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