Past Seminars

Academic year: September 2011 - September 2012

  • T-duality for massive stringy states: A world sheet perspective
    Jnanadeva Maharana (Bhubaneswar, India)

    Leuven – November 30, 2011

    We provide evidence for T-duality, from the worldsheet perspective, for massive excited levels of closed bosonic string. A simple scenario is envisaged where the target space is flat. In this frame work, it is argued that the vertex operators associated with the massive levels can be cast in an O(d,d) invariant form where d is the number of compact directions and the vertex operators are assumed to be independent of compact coordinates.
    Place:
      Leuven, Celestijnenlaan 200D room 05.11
    Time:   Wednesday, November 30, 2011 at 10.30
  • Diego Marqués (CEA Saclay)
    VUB/ULB – November 23, 2011


    Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
    Time:   Wednesday, November 23, 2011 at 10:30
  • Thomas Hertog (K.U.Leuven)
    VUB/ULB – November 23, 2011


    Place:  VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
    Time:   Wednesday, November 23, 2011 at 13:00
  • Higher-spin theories in odd dimensions
    Shailesh Lal (Harish-Chandra Research Institute)

    VUB/ULB– November 16, 2011


    We describe aspects of higher-spin theories in odd (specifically 3 and 5) dimensions. We first discuss the deformation of D=3 higher-spin theories by a topological mass term and provide evidence that the dual CFT is logarithmic. We then go on to compute the one-loop partition function of the higher-spin fields in AdS_5 and compare with the boundary spectrum. Central to these results are the heat kernel expressions for arbitrary-spin particles in AdS, which we shall review.
    Place:
      VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
    Time:   Wednesday, November 16, 2011 at 10:30
  • M5's, D4's, 5D SYM and instantons
    Neil Lambert (CERN Theory Division)

    VUB/ULB – November 16, 2011


    We will discuss the M5-brane and its relation to D4-branes. An important role is played by instantons and we conjecture that 5D SYM is an interesting QFT that is possibly finite.
    Place:
      VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
    Time:   Wednesday, November 16, 2011 at 13:0
  • Thermalization and entanglement following a non-relativistic holographic quench
    Esko Keski-Vakkuri (Helsinki University)
    VUB/ULB – November 9, 2011

    Recently it has become possible to construct toy models for thermalization from a far-from-equilibrium initial state in a strongly coupled relativistic quantum field theory. These toy models are based on the so-called holographic duality, where a quantum field theory is somewhat miraculously rewritted as a gravitational theory in one higher dimension. In my talk I discuss one way to modify these constructions to non-relativistic non-equilibrium dynamics.
    Place:
      VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
    Time:   Wednesday, November 9, 2011 at 10:30
  • M-theory and generalised geometry
    David Berman (Queen Mary)
    VUB/ULB – November 9, 2011


    We give an overview of recent developments in using generalised geometry to constract duality symmetric actions in M-theory.
    Place:
      VUB/ULB, Campus Plaine, building NO, 5th floor, Salle Solvay
    Time:   Wednesday, November 9, 2011 at 13:00
  • Sakura Schäfer-Nameki (King's College London)
    Leuven – October 26, 2011

    I will give an overview of recent developments in understanding global aspects of F-theory compactifications that are relevant for realizing supersymmetric GUTs, including the more formal aspects of resolution of singular CY fourfolds and construction of G-fluxes.
    Place:
      Leuven, Celestijnenlaan 200D room 05.11
    Time:   Wednesday, October 26, 2011 at 10.30
  • "Mellin amplitudes in AdS/CFT"
    Miguel Paulos (LPTHE, Paris)

    VUB/ULB – October 12, 2011

    We investigate the use of the embedding formalism and the Mellin transform in the calculation of tree-level conformal correlation functions in AdS/CFT. We evaluate 5- and 6-point Mellin amplitudes in φ^3 theory and even a 12-pt diagram in φ^4 theory, enabling us to conjecture a set of Feynman rules for scalar Mellin amplitudes. We also show how to use the same combination of Mellin transform and embedding formalism for amplitudes involving fields with spin. The complicated tensor structures which usually arise can be written as certain operators acting as projectors on much simpler index structures - essentially the same ones appearing in a flat space amplitude. Using these methods we are able to evaluate a four-point current diagram with current exchange in Yang-Mills theory.
    Place:  VUB/ULB, Campus Plaine, building NO, 9th floor, Salle des Professeurs
    Time:   Wednesday, October 12, 2011 at 10:30

  • Holographic Correlators of Giant Gravitons
    Konstantinos Zoubos (Niels Bohr Institute, Copenhagen)

    VUB/ULB – October 12, 2011


    The appearance of integrability in N=4 SYM has provided an unprecedented level of information about the planar spectrum of the theory. Recently, some attention has shifted from the spectrum to three-point functions of operators with large quantum numbers, aiming to ascertain whether integrability plays a similarly important role for these observables. I will discuss the computation, on both sides of the AdS/CFT correspondence, of three-point functions involving two "heavy" operators dual to giant gravitons and one "light" single-trace chiral primary, and point out an intriguing puzzle that arises when comparing the gravity and gauge theory results.
    Place:
      VUB/ULB, Campus Plaine, building NO, 9th floor, Salle des Professeurs
    Time:   Wednesday, October 12, 2011 at 13:00
  • "Curved Superspace"
    Nathan Seiberg (IAS, Princeton)

    Leuven – October 5, 2011

    A certain limit of supergravity “the rigid limit” leads us to a unified and efficient description of supersymmetric field theories in rigid curved spacetime. We will present the general formalism and will demonstrate it in a few examples. We will also summarize some of the new insights about the dynamics that such theories in curved spaces teach to.
    Place:  Leuven, Celestijnenlaan 200D room 05.11
    Time:   Wednesday, October 5, 2011 at 10.30

  • "Thermodynamics and instabilities of a strongly coupled anisotropic plasma"
    David Mateos (Barcelona)

    Leuven – October 5, 2011

    I will present a IIB supergravity solution dual to a spatially anisotropic finite-temperature N=4 super Yang-Mills plasma. I will discuss its thermodynamics and show that the phase diagram exhibits homogeneous and inhomogeneous (i.e. mixed) phases. In some regions the homogeneous phase displays instabilities reminiscent of those of weakly coupled plasmas. I will comment on similarities with QCD at finite baryon density and with the phenomenon of cavitation.
    Place:  Leuven, Celestijnenlaan 200D room 05.11
    Time:   Wednesday, October 5, 2011 at 13:00

 

 

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