Induced spin interactions in the early universe from discrete time quantum theory

By considering a system of spinning particles in an external magnetic field we demonstrate that the system develops non-local spin interactions due to discrete time quantum effects. Such interactions can lead to a domain like structure in the early universe possibly serving as generic seeds to large scale structure.     

Fundamental constants and higher-dimensional universe

In order to study the origin of the fundamental constants and Dirac's large number, a cosmological solution in vacuum is presented in a seven-dimensional universe which is defined by adding extra three coordinates (e ² G/c ⁴)^1/2, (hG/c ³)^1/2 and (Gm/c ²) to the four-dimensional spacetime coordinates. It has common features with Chodos-Detweiler's solution. The parameters appearing in this theory are estimated to meet the conditions required by the cosmological first-order phase transition and Dirac's large number hypothesis.     

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.     

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.     

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.     

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...     

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.     

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.     

Fundamental interactions

Trapped and stored charged particles, atoms and molecules offer a number of opportunities to measure exact values of important fundamental constants such as lepton magnetic anomalies, the fine structure constant and the electron mass. New Physics can be searched for by comparing precise measurements and highly accurate calculations of particle properties. Some recent experiments differ by a few standard deviations from standard theory predictions, such as the muon magnetic anomaly and ²¹Na β-decay; for a clarification further work is needed. This work is in part supported by the Dutch Stichting voor Fundamenteel Onderzoek der Materie under programme 48 (TRIμP).     

Scalar field fluctuations in the early universe

We compute the quantum fluctuations of a non-self-interacting but unstable scalar field of arbitrary mass during the period of inflation. Instead of treating the scalar field in a static De Sitter space, we begin with a scalar field in the Friedmann universe just before the start of inflation, and work out the dynamics of the growing quantum fluctuation of the field after it has entered into the inflationary epoch. We use the physically sensible method of Vilenkin to regularize the theory. We find that in all but two special cases the fluctuations produced are different from those in a static De Sitter space, and the effect of the finite width of the scalar field limits the growth of fluctuations.     

Resonant axion-photon conversion in the early universe

It is shown that a cosmological magnetic field of order 10⁻⁸−10⁻⁹ G in the present universe gives rise to resonant axion-photon conversion at earlier epochs. Two effects that arise from the conversion of thermal photons into axions are discussed in some detail: the possibility of a baryon-dominated universe due to an enhanced baryon-photon ratio, and distortion of the Wien part of the microwave background radiation.     

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.     

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.