Bulletin of the American Physical Society
APS April Meeting 2011
Volume 56, Number 4
Saturday–Tuesday, April 30–May 3 2011; Anaheim, California
Session E11: Theoretical Outlooks |
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Sponsoring Units: DPF Chair: David Saltzberg, University of California, Los Angeles Room: Garden 2 |
Saturday, April 30, 2011 3:30PM - 3:42PM |
E11.00001: Semper FI? Supercurrents, R-Symmetries, and the Status of Fayet-Iliopoulos Terms in Supergravity Keith Dienes Recently, there has been a great deal of discussion concerning the consistency of Fayet-Iliopoulos (FI) terms in supersymmetric theories which are also coupled to gravity. In this talk, I shall give an overview of this question, describe some new results, and review its current status. [Preview Abstract] |
Saturday, April 30, 2011 3:42PM - 3:54PM |
E11.00002: Codimension Two Branes: Examples Nelson Zamorano, Cesar Arias We study a six dimensional cosmological model with co-dimension two. The starting point is a general 6d metric ansatz in normal coordinates: $\,ds^2\,=\, d\rho^2 + e^{2B(\rho)} d\sigma^2 + e^{2W(\rho)} g_{\mu\nu}(x) dx^{\mu} dx^{\nu}$, where the submanifold defined by the 4d metric $g_{\mu\,\nu}$ represents our observable universe. One of the solutions display a conical singularity at $\rho\,=\,0$, opening the possibility that a four dimensional brane may be embedded there, following the the work of Bostok et al. [1]. Here we concentrate in the solution where $B(\rho)\,= \ln\left[\,A\,\sin\left(\sqrt{\Lambda/\,10}\,\rho\,\right)\,\right]$\,$\approx\,\ln\left(\sqrt{\Lambda/\,10}\,\rho\,\right)$, which generates a conical singularity at $\rho\,=\,0$. The presence of this $\delta(\rho)$ in the Einstein equations induces a cosmological constant on the brane. It is also possible to introduce a Gauss-Bonnet term in this solution. A future work considers a scalar field in the bulk and perturbations on the brane to generate other cosmological models.\\[4pt] [1] P. Bostock, R. Gregory, I. Navarro and J. Santiago, Phys. Rev. Letter,Vol 92,\,22,\,22160-1. [Preview Abstract] |
Saturday, April 30, 2011 3:54PM - 4:06PM |
E11.00003: A Holographic Josephson Junction Benson Way, Gary Horowitz, Jorge Santos We construct a gravitational dual of a Josephson junction. Calculations on the gravity side reproduce the standard relation between the current across the junction and the phase difference of the condensate. We also study the dependence of the maximum current on the temperature and size of the junction and reproduce familiar results. [Preview Abstract] |
Saturday, April 30, 2011 4:06PM - 4:18PM |
E11.00004: Quantum back-reaction from non-adiabatic changes Curtis Asplund, David Berenstein Motivated by the problem of thermalization in QFTs and the dual non-equilibrium BH dynamics, we examine a generic and non-trivial aspect of these phenomena, non-adiabatic changes, in a highly simplified setting. We consider a harmonic oscillator whose frequency depends on a second quantum variable $x$. Beginning with a classical analysis, we show how the system can be described by an improved adiabatic expansion with a velocity dependent force for $x$. We find an instability at a critical velocity beyond which the adiabatic (Born-Oppenheimer) approximation breaks down. We extend this calculation to the fully quantum system and to field theory and describe how to study fermions with similar techniques. Finally, we set up a model with an abrupt change in the oscillator whose quantum mechanics can be solved exactly so that one can study the effects of back-reaction of a fully non-adiabatic change in a controlled setting. We comment on applications of these general results to the physics of D-branes, inflation, and BHs in AdS/CFT. [Preview Abstract] |
Saturday, April 30, 2011 4:18PM - 4:30PM |
E11.00005: Mechanism for family replication in supersymmetric SO(10) Roland Allen The theory presented in arXiv 1101.0586 [hep-th] suggests a mechanism for family replication in supersymmetric SO(10): different solutions to a fourth-order nonlinear equation (in an internal space) belonging to the same SO(10) representation. In this talk explicit numerical solutions will be shown, and the general properties of solutions will be discussed. [Preview Abstract] |
Saturday, April 30, 2011 4:30PM - 4:42PM |
E11.00006: Heart of Darkness: The Significance of the Zeptobarn Scale for Neutralino Direct Detection David Sanford, Jonathan Feng The direct detection of dark matter through its elastic scattering off nucleons is among the most promising methods for establishing the particle identity of dark matter. The current bound on the spin-independent scattering cross section is $\sigma^{SI} < 40$~zb for dark matter masses $mneut \sim 100$~GeV, with improved sensitivities expected soon. We examine the implications of this progress for neutralino dark matter in a supersymmetric framework well-suited to dark matter studies that is simple and transparent, with models defined in terms of four weak-scale parameters. Robust constraints on electric dipole moments motivate large sfermion masses $\tilde{m} \agt 1$~TeV, effectively decoupling squarks and sleptons from neutralino dark matter phenomenology. In this case, we find characteristic cross sections in the narrow range $1~\mathrm{zb} \alt \sigma^{SI} \alt 40$~zb for $m_\chi \agt 70$~GeV. This range expands by at most a factor of two when relaxing model assumptions except in finely tuned regions, and does it change significantly due to varying the strange quark content of the nucleon, including the effects of galactic small-scale structure, or assuming other components of dark matter. Experiments are therefore rapidly entering the heart of dark matter-favored supersymmetry parameter space. [Preview Abstract] |
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