855 research outputs found
Nonperturbative analysis of the evolution of cosmological perturbations through a nonsingular bounce
In bouncing cosmology, the primordial fluctuations are generated in a cosmic
contraction phase before the bounce into the current expansion phase. For a
nonsingular bounce, curvature and anisotropy grow rapidly during the bouncing
phase, raising questions about the reliability of perturbative analysis. In
this paper, we study the evolution of adiabatic perturbations in a nonsingular
bounce by nonperturbative methods including numerical simulations of the
nonsingular bounce and the covariant formalism for calculating nonlinear
perturbations. We show that the bounce is disrupted in regions of the universe
with significant inhomogeneity and anisotropy over the background energy
density, but is achieved in regions that are relatively homogeneous and
isotropic. Sufficiently small perturbations, consistent with observational
constraints, can pass through the nonsingular bounce with negligible alteration
from nonlinearity. We follow scale invariant perturbations generated in a
matter-like contraction phase through the bounce. Their amplitude in the
expansion phase is determined by the growing mode in the contraction phase, and
the scale invariance is well preserved across the bounce.Comment: 38 pages + appendices, 22 figure
Recent Cases: Wills — Descent of Insurance Proceeds Covering Extinguished Specific Bequests
Two recent cases involving the disposition of proceeds of insurance policies covering property given by specific bequest and destroyed immediately before testator\u27s death reach apparently opposite, but readily distinguishable, results. In a Kansas case a farmer had bequeathed his realty to his children and his personality to his wife. A tornado destroyed the farm buildings and fatally injured the farmer. Held: the proceeds from insurance covering the farm buildings descended to the heirs of the realty. An Oklahoma case involved the accidental destruction of an insured automobile and consequent death of its owner. Held: the insurance proceeds went to the legatee of the personal estate; only the wreckage of the automobile went to the legatee of the car.
Both cases involved destruction of a specific bequest between the time of the execution of the will and death of the testator. In one the bequest was of personality; in the other it was of realty. Therein lies the distinction between the two cases and the basis for a reconciliation of their holdings
Oil and Gas—Effect of Entirety Clauses on Grantees Taking under Deeds Subject to Lease
Often the owner of land places it under an oil lease and later conveys fee interests or mineral or royalty interests in segregated tracts from the leased area. When oil is subsequently produced on some, but not all of the leased area, problems may arise as to the royalty rights of the lessor and the grantees. Specifically, is the right of each grantee to royalties modified by the fact that his tract is part of a larger leased area? The problem will be considered in the absence and in the presence of the contractual device known as the entirety clause.
Various types of conveyances may give rise to this problem: conveyance of an interest in the fee; conveyance of an interest in the minerals under the land; or conveyance of an interest in royalties. Unless otherwise indicated, “conveyance” henceforth in this note will refer to conveyance of interest in the minerals
Recent Cases: Constitutional Law — Freedom of Speech — Conviction for Speaking After Having Been Wrongfully Denied License To Do So
Defendant, a Jehovah\u27s Witness, was convicted of conducting a public meeting in a city park without first obtaining the license reÂquired by city ordinance. Defendant maintained that he had applied for such license, but had been wrongfully denied it. The New HampÂshire Supreme Court held the ordinance valid, and the conviction binding, notwithstanding the wrongfulness of the refusal to grant the license. Upon appeal to the United States Supreme Court, held: conviction affirmed. The refusal to grant the license was a wrongful contravention of purely ministerial powers conferred by the ordinance; but such wrongfulness was no defense to defendant\u27s violation of the ordinance by proceeding with the speech. His only remedy would have been a mandamus action
On the relation of the gravitino mass and the GUT parameters
In this article we consider the local supersymmetry breaking and the broken
SU(5) symmetry permisible by dilaton vacuum configuration in supergravity
theories. We establish the parameter relation of spontaneuos breaking of
supersymmetry and of the GUT theory.Comment: 12 pages, file written in Revtex forma
Scale invariance and critical gravitational collapse
We examine ways to write the Choptuik critical solution as the evolution of
scale invariant variables. It is shown that a system of scale invariant
variables proposed by one of the authors does not evolve periodically in the
Choptuik critical solution. We find a different system, based on maximal
slicing. This system does evolve periodically, and may generalize to the case
of axisymmetry or of no symmetry at all.Comment: 7 pages, 3 figures, Revtex, discussion modified to clarify
presentatio
Rapid Thermalization in Field Theory from Gravitational Collapse
Motivated by the duality with thermalization in field theory, we study
gravitational collapse of a minimally coupled massless scalar field in Einstein
gravity with a negative cosmological constant. We investigate the system
numerically and establish that for small values of the initial amplitude of the
scalar field there is no black hole formation, rather, the scalar field
performs an oscillatory motion typical of geodesics in AdS. For large enough
values of the amplitude of the scalar field we find black hole formation which
we detect numerically as the emergence of an apparent horizon. Using the time
of formation as an estimate for thermalization in the field theory we conclude
that thermalization occurs very rapidly, close to the causal bound for a very
wide range of black hole masses. We further study the thermalization time in
more detail as a function of the amplitude and the width of the initial
Gaussian scalar field profile and detect a rather mild structure.Comment: 5 pages, 4 figures. v2: References added, improved most grids by a
factor of 8, main results unchanged. v3 PRD versio
Numerical simulations of general gravitational singularities
This paper covers some of the current techniques and issues involved in
performing numerical simulations of the formation of singularities.Comment: This work was part of the 2006 AEI conference on New Frontiers in
Numerical Relativity and was published in an issue of Classical and Quantum
Gravity on that conferenc
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