Related papers: Formation of conserved charge at the de Sitter spa…
The main goal of this paper is to give an alternative interpretation of space-like and time-like extra dimensions as a primary factor for inflation in the early universe. We introduce the 5-dimensional perfect fluid and compare the…
Quantum gravity in 2+1 dimensions with a positive cosmological constant can be represented as an SL(2,C) Chern-Simons gauge theory. The symmetric vacuum of this theory is a degenerate configuration for which the gauge fields and spacetime…
We investigate the possibility that the dark matter abundance is sourced by the baryon/lepton asymmetry of the early Universe. It turns out that a Goldstone field of a local classically preserved symmetry in the Standard Model experiences a…
We relate the mechanism of matter creation in the universe after inflation to a simple and universal mathematical property of extended N > 1 supergravities and related compactifications of superstring theory. We show that in all such…
Cosmological acceleration is difficult to accommodate in theories of fundamental interactions involving supergravity and superstrings. An alternative is that the acceleration is not universal but happens in a large localized region, which…
Recently various phenomenological implications of the existence of extra space-time dimensions have been investigated. In this letter, we construct a model with realistic fermion mass hierarchy with (large) extra dimensions beyond the usual…
The scalar and electromagnetic fields produced by the geodesic and uniformly accelerated discrete charges in de Sitter spacetime are constructed by employing the conformal relation between de Sitter and Minkowski space. A special attention…
A scenario for the generation of the baryon asymmetry in the early Universe is proposed in which cosmic string loops, predicted by theories where the baryon and/or lepton numbers are gauged symmetries, collapse during the friction dominated…
The asymptotic symmetry group (ASG) at future null infinity (I^+) of four-dimensional de Sitter spacetimes is defined and shown to be given by the group of three-dimensional diffeomorphisms acting on I^+. Finite charges are constructed for…
We propose a scenario for the generation of baryon number asymmetry based on the inflaton decay in a radiative neutrino mass model extended with singlet scalars. In this scenario, lepton number asymmetry is produced through the decay of…
In a recent paper (JHEP {\bf 1508} (2015) 021), we have investigated hypersymmetry bounds in the context of simple anti-de Sitter hypergravity in $2+1$ dimensions. We showed that these bounds involved non linearly the spin-$2$ and spin-$4$…
The scalar and electromagnetic fields of charges uniformly accelerated in de Sitter spacetime are constructed. They represent the generalization of the Born solutions describing fields of two particles with hyperbolic motion in flat…
Supersymmetry plays a fundamental role in the radiative stability of many inflationary models. Spontaneous breaking of the symmetry inevitably leads to fields with masses of order the Hubble scale during inflation. When these fields couple…
Complex scalar fields charged under approximate $U(1)$ symmetries appear in well-motivated extensions of the Standard Model. One example is the field that contains the QCD axion field associated with the Peccei-Quinn symmetry; others…
We present aspects of a model which attempts to unify the creation of cold dark matter, a CP-violating baryon asymmetry, and also a small, residual vacuum energy density, in the early universe. The model contains a primary scalar (inflaton)…
Two moderate extensions of the minimal supersymmetric standard model are considered. The first one includes a U(1)_{B-L} gauge group, while the second is based on a left-right symmetric gauge group. In these models, hybrid inflation is…
We give a detailed review of construction of conserved quantities in extended theories of gravity for asymptotically maximally symmetric spacetimes and carry out explicit computations for various solutions. Our construction is based on the…
In theories with an infinite extra dimension, free particles localized on the brane can leak out to the extra space. We argue that if there were color confinement in the bulk, electrons would be more able to escape than quarks and than…
We will review the main aspects of a mechanism for the contemporary generation of the baryon and Dark Matter abundances from the out-of-equilibrium decay of a Wimp-like mother particle and briefly discuss a concrete realization in a…
We provide a very general argument showing that the Universe must have kept its quantum memories from an epoch much earlier than $60$ e-foldings before the end of inflation. The point is that a generic system of enhanced memory storage…