Casimir stress in spherical media when εμ = 1

1984 ◽  
Vol 62 (8) ◽  
pp. 805-810 ◽  
Author(s):  
I. Brevik ◽  
H. Kolbenstvedt

The radial and azimuthal stress components of the electromagnetic zero-point field are calculated inside and outside a spherical surface dividing two media of permeabilities μ1 and μ2. The corresponding permittivities ε1 and ε2 are such that εμ = 1 everywhere. Schwinger's source theory is used. In the inside region all stress components are negative, corresponding to a negative pressure. In the outside region the signs of the angular stress components are reversed, similar to the case for the energy density.

Author(s):  
Biswaranjan Dikshit

Cosmic inflation has presented solutions for a number of important cosmological problems, yet left some unanswered. In this paper, we present a cosmological model based on the quantization of the zero-point field which is consistent with empirical data, requires fewer assumptions, and presents answers to some of those unanswered questions. A comparison between standard cosmology and the theory presented in this paper is given below. Vacuum energy density: Standard inflationary model needs both Hubble’s constant and Matter density to estimate it. But, new cosmological model needs only Hubble’s constant. Non-vacuum energy density: Standard model can’t predict it. But, the new model can predict using only Hubble’s constant. Ratio of vacuum energy to total energy: Standard model can’t predict it. But, new model can predict it, that too without using Hubble’s constant. Energy conservation: In standard model, total energy is not conserved before inflation. But, in the new model, energy is conserved right from beginning of the universe whose net energy (including gravitational potential energy) is always zero. Flatness and homogeneity: Standard model needs Inflaton field with a specific potential energy distribution to explain it. But, new model doesn’t need any such hypothetical field, just the zero-point field is sufficient. Based on the new cosmological model, in the conclusion, realistic possibility for existence of multiverse and a mechanism for end of universe are discussed.


1998 ◽  
Vol 13 (38) ◽  
pp. 3069-3072
Author(s):  
L. C. GARCIA DE ANDRADE

Negative energy densities in spinning matter sources of non-Riemannian ultrastatic traversable wormholes require the spin energy density to be higher than the negative pressure or the radial tension. Since the radial tension necessary to support wormholes is higher than the spin density in practice, it seems very unlikely that wormholes supported by torsion may exist in nature. This result corroborates earlier results by Soleng against the construction of the closed time-like curves (CTC) in space–time geometries with spin and torsion. It also agrees with earlier results by Kerlick according to which Einstein–Cartan (EC) gravity torsion sometimes enhance the gravitational collapse instead of avoiding it.


A kink on a dislocation in an isotropic elastic medium is treated as a 'point defect’ with a certain mass, constrained to move along a line and subject to a radiation reaction. A value for the mass is obtained from the well know n stretched-string model, and the radiation reaction is found by calculating the rate at which an oscillating kink radiates energy into the medium . It is found that the kink has a scattering cross-section for elastic waves which i§ proportional to the square of its width. For long waves the cross-section is independent of frequency, in contrast to the case of ordinary point defects. A kink moving through an isotropic flux of elastic waves experiences a retarding force proportional to the product of its velocity and the energy density of the waves. In connexion with a similar result for the retarding force on a dislocation moving rigidly it has been suggested that the expression for the energy density should include the zero-point energy. A formal quantum -mechanical calculation shows that this is not so in the case of a kink.


2021 ◽  
Author(s):  
dale koehler

Abstract It is shown in the present work that the distorted-space model of matter as extended to extreme curvature limits results in characteristics mimicking those of galactic-holes. The distorted-geometry structures exhibit non-Newtonian features wherein the hole or core-region fields of the structure are energetically-repulsive (negative pressure), do not behave functionally in an r-4 manner and terminate at zero at the radial origin (no singularity). Of particular interest is that of r-6 energy-density behavior at structural radial distances near the core of the distortion, a region also displaying potential-well behavior.


Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1534
Author(s):  
Yehonatan Knoll

Cold dark-matter, as a solution to the so-called dark-matter problem, suffers from a major internal conflict: In order to dodge direct detection for so long, it must have an unobservably small (non gravitational) interaction with mundane matter, and yet it manages to ‘conspire’ with it such that, in single galaxies, its distribution can be inferred from that of mundane matter via the MOND phenomenology. This conflict is avoided if the missing, transparent component of the energy-momentum tensor is due to variations in some electromagnetic ‘zero point field’ (ZPF) which is sourced by mundane matter and contains both its advanced and retarded fields. The existence of a ZPF thus modulated by mundane matter, follows from a proper solution to the self-force problem of classical electrodynamics (CED), recently proposed by the author, which renders CED compatible with the statistical predictions of QM. The possibility that ‘dark matter’ is yet another, hitherto ignored facet of good-old classical electrodynamics, therefore seems no less plausible than it being a highly exotic and conspirative new form of matter. Tests for deciding between the two are proposed.


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