We formulate a theory combining the principles of scalar-tensor gravity and Rastall's proposal of a violation of the usual conservation laws. We obtain a scalar-tensor theory with two parameters ω and λ, the latter quantifying the violation of the usual conservation laws (λ = 1 corresponding to the General Relativity limit). The only exact spherically symmetric solution is that of Robinson-Bertotti besides the Schwarzschild solution. A PPN analysis reveals that General Relativity results are reproduced when λ = 0. The cosmological case displays a possibility of deceleration/acceleration or acceleration/deceleration transitions during the matter dominated phase depending on the values of the free parameters.
Incidence angle dependent elastic electron reflection curves in the 0 to 30 eV range are measured on Cu(ll1) and Ni(ll1) using target current regime. They are compared with the calculated ones. Computations are made very fast using a simple approximation. The extrema of the reflection energy derivative are shown to correspond unambigiously to definite critical points of bands. These points are mapped when the energies of the experimental extrema are compared with the calculated ones. Varying the incidence angle, in this way bands in the variety of Brillouin 7one directions may be investigated.
We show that hydrodynamical and field approaches in theory of cosmological
scalar perturbations are equivalent for a single medium. We also give relations
between notations introduced by V. Lukash, J. Bardeen, J. Bardeen et al. and G.
Chibisov and V. Mukhanov.Comment: 8 pages, no figures, submitted to Astronomy Report
In the paper we discuss the role of the axial U (1)A symmetry in the chiral phase transition using the U (N f )R × U (N f )L linear sigma model with two massless quark flavors. It is expected that above a certain temperature the axial U (1)A symmetry will be restored. A string-like static solution, the η string can be formed and detected in the ultrarelativistic heavy-ion collision process.
We briefly review the problem of generating cosmological flows of matter in GR (the genesis of universes), analyze models' shortcomings and their basic assumptions yet to be justified in physical cosmology. We propose a paradigm of cosmogenesis based on the class of spherically symmetric solutions with integrable singularity r = 0. They allow for geodesically complete geometries of black/white holes, which may comprise space-time regions with properties of cosmological flows. * Astrospace Centre of the Levedev Physical Institute.
We discuss the problem of singularities in general relativity and emphasize the distinction that should be made between what is understood to be mathematical and physical singularities. We revise examples of space-times that conventionally contain a singularity which, in a sense, does not manifest itself physically. A special attention is paid to the case of integrable singularities for which we propose a well-defined mathematical procedure used to extend the space-time beyond the singularity. We argue that this type of singularity may connect the interior of a black hole with a newly born universe (a space-time referred to as black-and-white hole) giving a resolution to the problem of initial high density and symmetry of the universe. We exemplify by presenting toy models of eternal and astrophysical black-and-white holes.
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