Single scale factor for the universe from the creation of radiation and matter till the present

For a long time, global fits of the electroweak sector of the standard model (SM) have been used to exploit measurements of electroweak precision observables at lepton colliders (LEP, SLC), together with measurements at hadron colliders (Tevatron, LHC) and accurate theoretical predictions at multi-loop level, to constrain free parameters of the SM, such as the Higgs and top masses. Today, all fundamental SM parameters entering these fits are experimentally determined, including information on the Higgs couplings, and the global fits are used as powerful tools to assess the validity of the theory and to constrain scenarios for new physics. Future measurements at the Large Hadron Collider (LHC) and the International Linear Collider (ILC) promise to improve the experimental precision of key observables used in the fits. This paper presents updated electroweak fit results using the latest NNLO theoretical predictions and prospects for the LHC and ILC. The impact of experimental and theoretical uncertainties is analysed in detail. We compare constraints from the electroweak fit on the Higgs couplings with direct LHC measurements, and we examine present and future prospects of these constraints using a model with modified couplings of the Higgs boson to fermions and bosons.     

Effect of density fluctuations on the expansion of the universe far from the singularity

The effect of fluctuations in the density of matter on the expansion of the universe far from the singularity is analyzed on the basis of a model with a three-dimensional space which is homogeneous and isotropie on the average. The fluctuations reduce the gravitational effect, retarding the expansion. This effect of the fluctuations increases as the expansion proceeds and can strongly affect the expansion velocity. An equation is derived for the age of the universe on the basis of this model. The age is expressed in terms of observable quantities: the Hubble constant and the acceleration parameter. It is shown that fluctuations lead to an increase in this age. It is concluded that fluctuations must be taken into account in studying the expansion of the observable universe.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 7–11, January, 1977.     

Borexino as a test of solar matter density fluctuations

This talk summarizes some results of our recent work focusing on the possibility to test solar matter density fluctuations by the future Borexino experiment.     

Late time cosmic acceleration of a flat matter dominated universe with constant vacuum energy

Matter and radiation densities are compared with a constant vacuum energy density of positive cosmological constant, from a few seconds of the universe till the present epoch. Epoch of acceleration is calculated by estimating baryonic density from consideration of finite thickness of last scattering surface and dark matter density from inflationary flatness condition. The calculated epoch of acceleration is found to be in good agreement with recent supernova observations.     

The law of temperature dependence of matter density in the very early universe

The law of temperature dependence of matter density in the very early Universe is derived.     

Holographic dark energy and the universe expansion acceleration

By incorporating the holographic principle in a time-depending Λ-term cosmology, new physical bounds on the arbitrary parameters of the model can be obtained. Considering then the dark energy as a purely geometric entity, for which no equation of state has to be introduced, it is shown that the resulting range of allowed values for the parameters may explain both the coincidence problem and the universe accelerated expansion, without resorting to any kind of additional structures.     

Cosmic matter and the nonexpanding universe

The authors examine how some observations involving plasma physics in space are compatible with a recent red-shift theory. An increasingly large number of observations consistently reveal the existence of a much larger amount of intergalactic matter than presently accepted. A radio signal coming from directions between galaxies is discussed. An average density of matter in space of about 0.01 atom/cm³ is derived. It is shown that this density of matter is compatible with many reliable observations. These results lead to a nonexpanding cosmological model     

Level density of a Fermi gas: average growth and fluctuations

We compute the level density of a two-component Fermi gas as a function of the number of particles, angular momentum, and excitation energy. The result includes smooth low-energy corrections to the leading Bethe term (connected to a generalization of the partition problem and Hardy-Ramanujan formula) plus oscillatory corrections that describe shell effects. When applied to nuclear level densities, the theory provides a unified formulation valid from low-lying states up to levels entering the continuum. The comparison with experimental data from neutron resonances gives excellent results.     

Scalar field fluctuations in the expanding universe and the new inflationary universe scenario

The behaviour of the scalar fied fluctuations in the exponentially expanding universe and their role in the new inflationary universe scenario are investigated.     

Quantum fluctuations in the new inflationary universe

The evolution of quantum fluctuations of a scalar field in de Sitter space is analyzed in the context of the new inflationary scenario. The duration of the inflationary phase is estimated and the problem of density perturbations resulting from quantum fluctuations of the Higgs field is discussed.     

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.     

The acceleration of the universe and the physics behind it

Using a general classification of dark enegy models in four classes, we discuss the complementarity of cosmological observations to tackle down the physics beyond the acceleration of our universe. We discuss the tests distinguishing the four classes and then focus on the dynamics of the perturbations in the Newtonian regime. We also exhibit explicitely models that have identical predictions for a subset of observations.     

Stimulated creation of quanta during inflation and the observable universe

Inflation provides a natural mechanism to account for the origin of cosmic structures. The generation of primordial inhomogeneities during inflation can be understood via the spontaneous creation of quanta from the vacuum. We show that when the corresponding stimulated creation of quanta is considered, the characteristics of the state of the universe at the onset of inflation are not diluted by the inflationary expansion and can be imprinted in the spectrum of primordial inhomogeneities. The non-gaussianities (particularly in the so-called squeezed configuration) in the cosmic microwave background and galaxy distribution can then tell us about the state of the universe that existed at the time when quantum field theory in curved spacetime first emerged as a plausible effective theory.     

Dark matter and dark energy of the universe

A possibility of existing spheres filled with a uniform constant scalar field in the Universe is shown. These spheres can act as “dark matter” and can be responsible for a decreasing behavior of the “ rotational” curved galaxies observed. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 9–19, April, 2006.     

The creation of the universe as a quantum phenomenon

Quantum creation of massy particles can occur in the cosmological context without cost of energy. This fact is seized upon to construct a causal open homogeneous isotropic cosmology. The universe is conceived as the response of matter and the gravitational field to a spontaneous pointlike disturbance. Its history unfolds in two stages, creation and free expansion. The first stage gives rise to a “fireball.” The free expansion is extrapolated back to the “fireball.” The latter thus replaces the “big-bang,” thereby avoiding an initial singularity. Though not intrinsic to the theory it does suggest the interpretation of the cosmological part of the gravitational field as the scalar dilaton that is encountered in the dynamical generation of mass in conformally invariant theory.     

Age of the universe and the density parameter

An exact formula for the age of the universe in terms of the density parameter is found that may be used instead of the approximate one in current use, among other purposes, for the estimate of an upper bound of relic particles in the present universe.     

Dark matter and the baryon asymmetry of the universe

We present a mechanism to generate the baryon asymmetry of the Universe which preserves the net baryon number created in the big bang. If dark matter particles carry baryon number Bx, and sigmaxannih相似文献