Browsing by Subject "High Energy Physics - Theory"

Now showing 1 - 3 of 3
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    Application of AdS/CFT in Nuclear Physics
    (2014) Pahlavani, M R; Morad, R
    We review some recent progress in studying the nuclear physics especially nucleon-nucleon (NN) force within the gauge-gravity duality, in context of noncritical string theory. Our main focus is on the holographic QCD model based on the AdS6 background. We explain the noncritical holography model and obtain the vector-meson spectrum and pion decay constant. Also, we study the NN interaction in this frame and calculate the nucleonmeson coupling constants. A further topic covered is a toy model for calculating the light nuclei potential. In particular, we calculate the light nuclei binding energies and also excited energies of some available excited states. We compare our results with the results of other nuclear models and also with the experimental data. Moreover, we describe some other issues which are studied using the gauge-gravity duality.
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    Open Access
    Are braneworlds born isotropic?
    (2004) Dunsby, Peter K S; Goheer, Naureen; Bruni, Marco; Coley, Alan
    It has recently been suggested that an isotropic singularity may be a generic feature of brane cosmologies, even in the inhomogeneous case. Using the covariant and gauge-invariant approach we present a detailed analysis of linear perturbations of the isotropic model ${cal F}_b$ which is a past attractor in the phase space of homogeneous Bianchi models on the brane. We find that for matter with an equation of state parameter $gamma > 1$, the dimensionless variables representing generic anisotropic and inhomogeneous perturbations decay as $tto 0$, showing that the model ${cal F}_b$ is asymptotically stable in the past. We conclude that brane universes are born with isotropy naturally built-in, contrary to standard cosmology. The observed large-scale homogeneity and isotropy of the universe can therefore be explained as a consequence of the initial conditions if the brane-world paradigm represents a description of the very early universe. Comment: Changed to match published version
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    Particle-vortex duality in topological insulators and superconductors
    (2017) Murugan, Jeff; Nastase, Horatiu
    We investigate the origins and implications of the duality between topological insulators and topological superconductors in three and four spacetime dimensions. In the latter, the duality transformation can be made at the level of the path integral in the standard way, while in three dimensions, it takes the form of “self-duality in odd dimensions”. In this sense, it is closely related to the particle-vortex duality of planar systems. In particular, we use this to elaborate on Son’s conjecture that a three dimensional Dirac fermion that can be thought of as the surface mode of a four dimensional topological insulator is dual to a composite fermion.