Matter-Antimatter Asymmetry Induced by a Running Vacuum Coupling

We show that a CP-violating interaction induced by a derivative coupling between the running vacuum and a non-conserving baryon current may dynamically break CPT and trigger baryogenesis through an effective chemical potential. By assuming a non-singular class of running vacuum cosmologies which provides a complete cosmic history (from an early inflationary de Sitter stage to the present day quasi-de Sitter acceleration), it is found that an acceptable baryon asymmetry is generated for many different choices of the model parameters. It is interesting that the same ingredient (running vacuum energy density) addresses several open cosmological questions/problems: avoids the initial singularity, provides a smooth exit for primordial inflation, alleviates both the coincidence and the cosmological constant problems, and, finally, is also capable of explaining the generation of matter-antimatter asymmetry in the very early Universe.Comment: 6 pages two column format, 1 table. Published version EPJ

Electrons as quasi-bosons in magnetic white dwarfs

A white dwarf star achieves its equilibrium from the balancing of the gravitational compression against the Fermi degeneracy pressure of the electron gas. In field theory there are examples (e.g. the monopole-charge system) where a strong magnetic field can transform a boson into a fermion or a fermion into a boson. In some condensed matter systems (e.g. fractional quantum Hall systems) a strong magnetic field can transform electrons into effective fermions, or effective anyons. Based on these examples we investigate the possibility that the strong magnetic fields of some white dwarfs may transform some fraction of the electrons into effective bosons. This could have consequences for the structure of highly magnetized white dwarfs. It would alter the mass-radius relationship, and in certain instances one could envision a scenario where a white dwarf below the Chandrasekhar limit could nevertheless collapse into a neutron star due to a weakening of the electron degeneracy pressure. In addition the transformation of electrons into effective bosons could result in the electrons Bose condensing, which could speed up the cooling rate of white dwarfs.Comment: 10 pages. To be published IJMP

Anti-de-Sitter Island-Universes from 5D Standing Waves

We construct simple standing wave solutions in a 5D space-time with a ghost scalar field. The nodes of these standing waves are 'islands' of 4D Minkowski space-time. For the 5D model with increasing (decreasing) warp factor there are a finite (infinite) number of nodes and thus Minkowski island-universes having different parameters, such as gravitational and cosmological constants. This feature is similar to the assumptions of the landscape models, which postulate a large number of universes with different parameters. This standing wave solution also provides a new localization mechanism - matter fields can reside only on Minkowski 'islands', where the background space-time does not oscillate.Comment: 14 page pre-print format. Discussion about connection to Weyl gravity added and "E&M" localization method added. To be published MPL

Brane in 6D with increasing gravitational trapping potential

A new solution to Einstein equations in (1+5)-spacetime with an embedded (1+3) brane is given. This solution localizes the zero modes of all kinds of matter fields and 4-gravity on the (1+3) brane by an increasing, transverse gravitational potential. This localization occurs despite the fact that the gravitational potential is not a decreasing exponential, and asymptotically approaches a finite value rather than zero.Comment: Revised paper. 6 pages, revtex 4. to be published in PR

On the relation between Unruh and Sokolov--Ternov effects

We show that the Sokolov--Ternov effect -- the depolarization of particles in storage rings coming from synchrotron radiation due to spin flip transitions -- is physically equivalent to the Unruh effect for circular acceleration if one uses a spin 1/2 particle as the Unruh--DeWitt detector. It is shown that for the electron, with gyromagnetic number $g \approx 2$, the exponential contribution to the polarization, which usually characterizes the Unruh effect, is "hidden" in the standard Sokolov-Ternov effect making it hard to observe. Thus, our conclusions are different in detail from previous work.Comment: 23 pages, no figure

Gauge procedure with gauge fields of various ranks

The standard procedure for making a global phase symmetry local involves the introduction of a rank 1, vector field in the definition of the covariant derivative. Here it is shown that it is possible to gauge a phase symmetry using fields of various ranks. In contrast to other formulations of higher rank gauge fields we begin with the coupling of the gauge field to some matter field, and then derive the gauge invariant, field strength tensor. Some of these gauge theories are similar to general relativity in that their covariant derivatives involve derivatives of the rank n gauge field rather than just the gauge field. For general relativity the covariant derivative involves the Christoffel symbols which are written in terms of derivatives of the metric tensor. Many (but not all) of the Lagrangians that we find for these higher rank gauge theories lead to nonrenormalizable quantum theories which is also similar to general relativity.Comment: References adde

De Sitter space and perpetuum mobile

We give general arguments that any interacting non--conformal {\it classical} field theory in de Sitter space leads to the possibility of constructing a perpetuum mobile. The arguments are based on the observation that massive free falling particles can radiate other massive particles on the classical level as seen by the free falling observer. The intensity of the radiation process is non-zero even for particles with any finite mass, i.e. with a wavelength which is within the causal domain. Hence, we conclude that either de Sitter space can not exist eternally or that one can build a perpetuum mobile.Comment: 11 pages revtex, no figures. Added discussion to strengthen conclusio