469 research outputs found

    Exotic Low Density Fermion States in the Two Measures Field Theory: Neutrino Dark Energy

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    We study a new field theory effect in the cosmological context in the Two Measures Field Theory (TMT). TMT is an alternative gravity and matter field theory where the gravitational interaction of fermionic matter is reduced to that of General Relativity when the energy density of the fermion matter is much larger than the dark energy density. In this case also the 5-th force problem is solved automatically. In the opposite limit, where the magnitudes of fermionic energy density and scalar field dark energy density become comparable, nonrelativistic fermions can participate in the cosmological expansion in a very unusual manner. Some of the features of such states in a toy model of the late time universe filled with homogeneous scalar field and uniformly distributed nonrelativistic neutrinos: neutrino mass increases as m ~ a^{3/2}; the neutrino gas equation-of-state approaches w=-1, i.e. neutrinos behave as a sort of dark energy; the total (scalar field + neutrino) equation-of-state also approaches w=-1; the total energy density of such universe is less than it would be in the universe filled with the scalar field alone. An analytic solution is presented. A domain structure of the dark energy seems to be possible. We speculate that decays of the CLEP state neutrinos may be both an origin of cosmic rays and responsible for a late super-acceleration of the universe. In this sense the CLEP states exhibit simultaneously new physics at very low densities and for very high particle masses.Comment: 47 pages, accepted for publication in Int.J.Mod.Phys.

    Fine Tuning Free Paradigm of Two Measures Theory: K-Essence, Absence of Initial Singularity of the Curvature and Inflation with Graceful Exit to Zero Cosmological Constant State

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    The dilaton-gravity sector of the Two Measures Field Theory (TMT)is explored in detail in the context of cosmology. The model possesses scale invariance which is spontaneously broken due to the intrinsic features of the TMT dynamics. The effective model represents an explicit example of the effective k-essence resulting from first principles without any exotic term in the fundamental action. Depending of the choice of regions in the parameter space, TMT exhibits different possible outputs for cosmological dynamics: a) Absence of initial singularity of the curvature while its time derivative is singular. This is a sort of "sudden" singularities studied by Barrow on purely kinematic grounds. b) Power law inflation in the subsequent stage of evolution. Depending on the region in the parameter space (but without fine tuning) the inflation ends with a graceful exit either into the state with zero cosmological constant (CC) or into the state driven by both a small CC and the field phi with a quintessence-like potential. c) Possibility of resolution of the old CC problem. From the point of view of TMT, it becomes clear why the old CC problem cannot be solved (without fine tuning) in conventional field theories. d) TMT enables two ways for achieving small CC without fine tuning of dimensionfull parameters: either by a seesaw type mechanism or due to a correspondence principle between TMT and conventional field theories (i.e theories with only the measure of integration sqrt{-g} in the action. e) There is a wide range of the parameters such that in the late time universe: the equation-of-state w=p/\rho <-1; w asymptotically (as t\to\infty) approaches -1 from below; \rho approaches a constant, the smallness of which does not require fine tuning of dimensionfull parameters.Comment: 37 pages, 20 figures. Minor misprints corrected, reference added. The final version published in Phys. Rev.

    Effect of Electron Energy Distribution Function on Power Deposition and Plasma Density in an Inductively Coupled Discharge at Very Low Pressures

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    A self-consistent 1-D model was developed to study the effect of the electron energy distribution function (EEDF) on power deposition and plasma density profiles in a planar inductively coupled plasma (ICP) in the non-local regime (pressure < 10 mTorr). The model consisted of three modules: (1) an electron energy distribution function (EEDF) module to compute the non-Maxwellian EEDF, (2) a non-local electron kinetics module to predict the non-local electron conductivity, RF current, electric field and power deposition profiles in the non-uniform plasma, and (3) a heavy species transport module to solve for the ion density and velocity profiles as well as the metastable density. Results using the non-Maxwellian EEDF model were compared with predictions using a Maxwellian EEDF, under otherwise identical conditions. The RF electric field, current, and power deposition profiles were different, especially at 1mTorr, for which the electron effective mean free path was larger than the skin depth. The plasma density predicted by the Maxwellian EEDF was up to 93% larger for the conditions examined. Thus, the non-Maxwellian EEDF must be accounted for in modeling ICPs at very low pressures.Comment: 19 pages submitted to Plasma Sources Sci. Techno

    Anomalous Capacitive Sheath with Deep Radio Frequency Electric Field Penetration

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    A novel nonlinear effect of anomalously deep penetration of an external radio frequency electric field into a plasma is discribed. A self-consistent kinetic treatment reveals a transition region between the sheath and the plasma. Because of the electron velocity modulation in the sheath, bunches in the energetic electron density are formed in the transition region adjusted to the sheath. The width of the region is of order VT/ωV_{T}/\omega, where V_{T} is the electron thermal velocity, and ω\omega is frequency of the electric field. The presence of the electric field in the transition region results in a cooling of the energetic electrons and an additional heating of the cold electrons in comparison with the case when the transition region is neglected.Comment: 14,4 figure

    Constructing Client-Server Multi-Player Asynchronous Networked Games Using a Single-Computer Model

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    We examine the process of creating asynchronous networked games by applying systematic transformations to their single-computer analogues, identify the need for such transformations, and propose a simple system of rules for them. In developing these rules, our primary concerns are comparing the flow of events in single-processor and networked games and examining the restrictions and limitations resulting from speed considerations. Although this paper only discusses games, the transformation rides may apply to any networked application with asynchronous data input and exchange

    Ways of Transition to Clean Energy Use: Two Methodological Approaches

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    The combustion of fossil fuels for the production of energy has already resulted in significant modifications of the earth's environment, primarily through the emissions of carbon dioxide, sulfur dioxide, nitrogen oxides, and particulates. The modern world primary energy consumption patterns and its trends lead to the utilization of dirtier and more expensive fossil fuels. The desire to protect the environment is contradictory Lo such structural changes in energy like the broader use of coal as substitution for liquid fuels, taking into account the depletion of coal deposits with low sulfur contents. Previous studies carried out at IIASA, in the FRG, the US, the USSR and other countries, formulate one long-term technological strategy that might limit pollutant emissions sufficiently to permit an efficient and ecologically sustainable development of the world's energy consumption patterns. This technological strategy is based on the implementation of the so-called Integrated Energy Systems (IES) or Integrated Energy-Chemical Systems (IECS). The basic idea of IES incorporates the decomposition and purification of primary fossil energy inputs before combustion, the integration of these decomposed (clean) products and the allocation of them in line with the requirements for final energy. Thus, Integrated Energy Systems represent a concept for providing a flexible range of final energy forms from varying inputs of different primary energy sources. Other potential advantages include improved performance of the whole energy system, such as higher efficiencies and lower environmental impacts. The joint report of the Kernforschungsanlage Julich (KFA), Julich, FRG and the Siberian Energy Institute (SEI), Irkutsk, USSR describes the concepts, methodological approaches, and preliminary results of the analysis of technological options and technoeconomic properties of the different types of integrated energy systems. The study of KFA and SEI, based on the cooperation with the International Institute for Applied Systems Analysis, emphasizes the common viewpoint that the idea of integrated energy systems constitutes an essential basis for new studies on energy systems with a high degree of utilizing primary energy sources and with low emissions

    Cosmological Parameter Determination from Counts of Galaxies

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    We study constraints that anticipated DEEP survey galaxy counts versus redshift data will place on cosmological model parameters in models with and without a constant or time-variable cosmological constant Λ\Lambda. This data will result in fairly tight constraints on these parameters. For example, if all other parameters of a spatially-flat model with a constant Λ\Lambda are known, the galaxy counts data should constrain the nonrelativistic matter density parameter Ω0\Omega_0 to about 5% (10%, 1.5%) at 1 σ\sigma with neutral (worst case, best case) assumptions about data quality.Comment: 15 pages, 6 figure
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