37,827 research outputs found

    Law Behind Second Law of Thermodynamics --Unification with Cosmology--

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    In an abstract setting of a general classical mechanical system as a model for the universe we set up a general formalism for a law behind the second law of thermodynamics, i.e. really for "initial conditions". We propose a unification with the other laws by requiring similar symmetry and locality properties.Comment: 17 page

    On the smallness of the cosmological constant in SUGRA models

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    In no--scale supergravity global symmetries protect local supersymmetry and a zero value for the cosmological constant. We consider the breakdown of these symmetries and present a minimal SUGRA model motivated by the multiple point principle, in which the total vacuum energy density is naturally tiny. In order to reproduce the observed value of the cosmological constant and preserve gauge coupling unification, an additional pair of 5+5ˉ5+\bar{5}--plets of superfields has to be included in the particle content of the considered model. These extra fields have masses of the order of the supersymmetry breaking scale; so they can be detected at future colliders. We also discuss the supersymmetry breakdown and possible solution of the cosmological constant problem by MPP in models with an enlarged gauge symmetry.Comment: 28 pages, 3 figures, some minor changes to the text, references adde

    Multiple point principle as a mechanism for the suppression of FCNC and CP--violation phenomena in the 2HDM

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    We argue that multiple point principle (MPP) can be used to ensure CP conservation and the absence of flavour changing neutral currents within the two Higgs doublet model (2HDM). We also discuss Higgs phenomenology in the MPP inspired 2HDM.Comment: Submitted for the SUSY07 proceedings, 4 pages, LaTeX, 2 eps figures,CERN preprint number added, references update

    Gravitational Lorentz anomaly from the overlap formula in 2-dimensions

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    In this letter we show that the overlap formulation of chiral gauge theories correctly reproduces the gravitational Lorentz anomaly in 2-dimensions. This formulation has been recently suggested as a solution to the fermion doubling problem on the lattice. The well known response to general coordinate transformations of the effective action of Weyl fermions coupled to gravity in 2-dimensions can also be recovered.Comment: 7 pages, late

    The spatial relation between the event horizon and trapping horizon

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    The relation between event horizons and trapping horizons is investigated in a number of different situations with emphasis on their role in thermodynamics. A notion of constant change is introduced that in certain situations allows the location of the event horizon to be found locally. When the black hole is accreting matter the difference in area between the two different horizons can be many orders of magnitude larger than the Planck area. When the black hole is evaporating the difference is small on the Planck scale. A model is introduced that shows how trapping horizons can be expected to appear outside the event horizon before the black hole starts to evaporate. Finally a modified definition is introduced to invariantly define the location of the trapping horizon under a conformal transformation. In this case the trapping horizon is not always a marginally outer trapped surface.Comment: 16 pages, 1 figur

    Why Nature has made a choice of one time and three space coordinates?

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    We propose a possible answer to one of the most exciting open questions in physics and cosmology, that is the question why we seem to experience four- dimensional space-time with three ordinary and one time dimensions. We have known for more than 70 years that (elementary) particles have spin degrees of freedom, we also know that besides spin they also have charge degrees of freedom, both degrees of freedom in addition to the position and momentum degrees of freedom. We may call these ''internal degrees of freedom '' the ''internal space'' and we can think of all the different particles, like quarks and leptons, as being different internal states of the same particle. The question then naturally arises: Is the choice of the Minkowski metric and the four-dimensional space-time influenced by the ''internal space''? Making assumptions (such as particles being in first approximation massless) about the equations of motion, we argue for restrictions on the number of space and time dimensions. (Actually the Standard model predicts and experiments confirm that elementary particles are massless until interactions switch on masses.) Accepting our explanation of the space-time signature and the number of dimensions would be a point supporting (further) the importance of the ''internal space''.Comment: 13 pages, LaTe

    Collective Fields for QCD

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    A gauge-symmetric approach to effective Lagrangians is described with special emphasis on derivations of effective low-energy Lagrangians from QCD. The examples we discuss are based on exact rewritings of cut-off QCD in terms of new collective degrees of freedom. These cut-off Lagrangians are thus ``effective'' in the sense that they explicitly contain some of the physical long-distance degrees of freedom from the outset.(Talk presented by P.H. Damgaard at the workshop on ``Quantum Field Theoretical Methods in High Energy Physics'', Kyffhauser, Germany, Sept. 1993. To appear in those proceedings).Comment: LaTeX, 12 pages, CERN--TH-7035/9

    On the Smallness of the Cosmological Constant in SUGRA Models Inspired by Degenerate Vacua

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    In the no-scale supergravity global symmetries protect local supersymmetry and a zero value for the cosmological constant. The breakdown of these symmetries, which ensures the vanishing of the vacuum energy density, results in a set of degenerate vacua with broken and unbroken supersymmetry leading to the natural realisation of the multiple point principle (MPP). In the MPP inspired SUGRA models the cosmological constant is naturally tiny.Comment: Parallel talk at SUSY09, Boston, USA, June 2009, 5 page
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