Rotation of the early universe

The evolution of the rotational velocity for the early expanding universe is analyzed. The possibility of a Planck rotational velocity is discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 37–40, December, 1985.     

Quantum mechanics of the early universe

Quantum tunneling of the universe from nothing into a de Sitter vacuum, interpreted as the birth of the universe from a vacuum, is considered. Vilenkin's results are generalized by allowing for strings, domain walls, and various kinds of compressed matter that contribute to the potential through which the tunneling occurs. The energy spectrum of the universe in the quantum pre-de Sitter stage, the coefficient of passage through the potential barrier, which describes the probability of birth of the universe, and the conditions of applicability of the quasi-classical approximation in the calculation of these quantities are found.Brainstorm MNTP, Moscow. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 78–82, April, 1995.     

The early Weyl universe

The consequences of a period of Weyl invariance in the early universe are investigated. It is argued that the natural outcome of such a period is a Kaluza-Klein style compactification of an internal space in which any time variation of the scale factor of this space is absorbed (via a Weyl transformation) into the gravitational coupling. A five-dimensional test model is shown to undergo exponential inflation of the space-time sector due to a false vacuum state of the non-metric part of the connection.     

Fundamental interactions in the early universe

A unified approach to fundamental interactions as explored earlier is further elaborated and its consequences for the early universe studied especially in connection with the energy dependence of the coupling constants.     

Neutrino oscillations and the early universe

The observational and theoretical status of neutrino oscillations in connection with solar and atmospheric neutrino anomalies is presented briefly. The effect of neutrino oscillations on the evolution of the early Universe is discussed in detail. A short review is given of the standard Big Bang Nucleosynthesis (BBN) and the influence of resonant and non-resonant neutrino oscillations on active neutrinos and on primordial synthesis of He-4. BBN cosmological constraints on neutrino oscillation parameters are discussed.     

Nonequilibrium in the very early universe

It is argued that the small horizon when the universe was close to the Planck temperature restricted the possible energies of elementary particles, preventing them from being in full thermal equilibrium. Grand unified particle interactions seem unlikely to have thermalized the universe much before the temperature fell to the mass scale of the baryon-number violating bosons.     

Matter production in the early universe

The coupled Dirac-Einstein equations with a negative cosmological constant for an open FRW universe are studied in detail. The corresponding solutions admit bounces ( minimal radius) of the universe such that the matter energy in any comoving 3-volume is either increased or decreased during the bounce according to whether the bounce pressure of the spinor field is appropriately negative or not. If matter is generated (annihilated) during a bounce, the universe subsequently becomes larger (smaller) than before the bounce. Therefore matter can be generated only during the growth of the universe, but it is annihilated again during the subsequent shrinking phase, which together with the growing phase forms a cosmic supercycle.     

Particle asymmetries in the early universe

The total lepton asymmetry l=∑_fl_f in our universe is only poorly constrained by theories and experiments. It might be orders of magnitudes larger than the observed baryon asymmetry b?O(10⁻¹⁰), |l|/b≤O(10⁹). We found that the dynamics of the cosmic QCD transition changes for large asymmetries. Predictions for asymmetries in a single flavour l_f allow even larger values. We find that asymmetries of l_f≤O(1) in single or two flavours may change the relic abundance of WIMPs. However, large lepton and large individual lepton flavour asymmetries influence significantly the dynamics of the early universe between the electroweak phase transition and the onset of neutrino oscillations.     

Graviton viscosity in the early universe

Second viscosity can have important effects in early stages of cosmological models. Here it is shown that nonlinear processes involving gravitons in the early universe might have given rise to such a viscosity.     

QCD development in the early universe

Physics of Atomic Nuclei - The high-energy limit of Quantum Chromodynamics is generated by the contraction of its gauge groups. Contraction parameters are taken identical with those of the...