64 research outputs found

    Real-time quantum field theory at finite temperature in an inhomogeneous media

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    The method of the real time perturbative calculations of nonequilibrium averages is generalised to the case of varying chemical potential. Calculations are performed in the frame of Zubarev's nonequilibrium density matrix approach. In this approach perturbations of temperature and other thermodynamical parameters are taken into account explicitly including nonlinear terms. It differs from the Schwinger-Keldysh approach through the choice of more general initial conditions for the density matrix.Comment: 10 LaTeX pages, 1 LaTeX figure included in main pape

    Women in Public Relations in Georgia. EUPRERA Report Vol. 2, No. 3

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    Observation of new quantum interference effect in solids

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    In order to achieve quantum interference of free electrons inside a solid, we have modified the geometry of the solid so that de Broglie waves interfere destructively inside the solid. Quantum interference of de Broglie waves leads to a reduction in the density of possible quantum states of electrons inside the solid and increases the Fermi energy level. This effect was studied theoretically within the limit of the quantum theory of free electrons inside the metal. It has been shown that if a metal surface is modified with patterned indents, the Fermi energy level will increase and consequently the electron work function will decrease. This effect was studied experimentally in both Au and SiO2 thin films of special geometry and structure. Work function reductions of 0.5 eV in Au films and 0.2 eV in SiO2 films were observed. Comparative measurements of work function were made using the Kelvin Probe method based on compensation of internal contact potential difference. Electron emission from the same thin films was studied by two independent research groups using Photoelectron Emission Microscopy (PEEM).Comment: 11 pages, 5 figure

    Non-equilibrium symmetry restoration beyond one loop

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    We calculate the strength of symmetry restoration effects in highly non-equilibrium states which can arise, for example, during preheating after inflation. We show that in certain parameter range the one-loop results are unstable, requiring summation of multiloop diagrams. We solve this problem for the O(N)O(N) model in the large NN-limit and show that the symmetry restoration may be less effective than what predicted by the one-loop estimate.Comment: Latex, 12 pages, 2 postscript figure

    C-V characterization and electric parameters of ZrO2 received by UV stimulated plasma anodizing

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    Low temperature technologies creating metals oxides are a promising solution for formation integral circuit elements. In this report the electric properties of zirconia (ZrO2) received by low temperature (~400oC) UV stimulated plasma anodizing have been investigated. Zirconia is a potential high-k dielectric material with potential applications as a gate insulator in transistors. This dielectric distinguished by good electric parameters. For this purpose, we used C-V characterization technique and calculate dielectric constant, flatband voltage, threshold voltage, bulk potential, work function, oxide effective charge, charge concentration. The C-V measurement was carried out on Keithley Instrument Semiconductor Parameter Analyzer 4200, oxide thickness was measured by reflectometer – MprobeVis System

    Problems of Perturbation Series in Non-Equilibrium Quantum Field Theories

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    In the standard framework of non-equilibrium quantum field theories, the pinch singularities associated to multiple products of δ\delta-functions do not cancel in a perturbative expansion unless the particle distributions are those for a system in thermal and chemical equilibrium.Comment: 10 pages, 2 figures, Cern preprint CERN-TH.7271/9

    Minimal Mixing of Quarks and Leptons in the SU(3) Theory of Flavour

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    We argue that flavour mixing, both in the quark and lepton sector, follows the minimal mixing pattern, according to which the whole of this mixing is basically determined by the physical mass generation for the first family of fermions. So, in the chiral symmetry limit when the masses of the lightest (uu and dd) quarks vanish, all the quark mixing angles vanish. This minimal pattern is shown to fit extremely well the already established CKM matrix elements and to give fairly distinctive predictions for the as yet poorly known ones. Remarkably, together with generically small quark mixing, it also leads to large neutrino mixing, provided that neutrino masses appear through the ordinary ``see-saw'' mechanism. It is natural to think that this minimal flavour mixing pattern presupposes some underlying family symmetry, treating families of quarks and leptons in a special way. Indeed, we have found a local chiral SU(3)FSU(3)_{F} family symmetry model which leads, through its dominant symmetry breaking vacuum configuration, to a natural realization of the proposed minimal mechanism. It can also naturally generate the quark and lepton mass hierarchies. Furthermore spontaneous CP violation is possible, leading to a maximal CP violating phase δ=π2\delta =\frac{\pi}{2}, in the framework of the MSSM extended by a high-scale SU(3)FSU(3)_{F} chiral family symmetry.Comment: 52 pages, LaTex, no figures; some typos corrected; journal versio
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