Numerical approaches to holography, quantum gravity and cosmology

UTC
Higgs Centre for Theoretical Physics

Higgs Centre for Theoretical Physics

James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD UK
Description
Holographic AdS/CFT duality and lattice gauge theory are leading non-perturbative approaches to investigate quantum gravity and strongly coupled quantum field theories. Extensive work is ongoing to apply both techniques to broader classes of systems, leading to a growing number of connections between them. Numerical analyses in particular are becoming increasingly important as computational capabilities continue to improve, motivating the development and dissemination of new or improved methods. Representative applications range from numerical relativity calculations of black hole dynamics and non-stationary spacetimes dual to far-from-equilibrium QFTs, to lattice studies of gauge theories with near-conformal dynamics, supersymmetry, or a large number of colours. Important successes of these ideas have been found in matching quantum field theory calculations in 0+1 dimensions with string theory predictions in 9+1 dimensions for black hole entropies with large D0-brane charge. Many advances have also been made recently in studying lattice gauge theories with some supersymmetry and near a conformal limit. The purpose of this workshop is to bring together the different communities of theoretical physicists who use numerical methods to investigate these types of questions. The programme of 16 invited talks over four days, 21--24 May, will leave abundant time for discussions and informal exchanges. By reviewing new developments within each community and fostering communication between them we aim to identify common ground, inspire new ideas and stimulate more rapid progress.
    • 09:00 09:30
      Welcome & coffee
    • 09:30 12:30
      Session 1
      • 09:30
        Kaluza-Klein black holes and their role in holography 1h 15m
        Speaker: Dr Toby Wiseman (Imperial College, London)
        Slides
      • 10:45
        Coffee break 30m
      • 11:15
        Superstrings on lattice 1h 15m
        Speaker: Dr Valentina Forini (City, University of London)
        Slides
    • 12:30 14:00
      Lunch & discussions
    • 14:00 17:20
      Session 2
      • 14:00
        Numerical methods for solving the Einstein equation in higher dimensions and in AdS with Cauchy evolution 1h 15m
        Speaker: Dr Pau Figueras (Queen Mary, University of London)
        Slides
      • 15:15
        Coffee break 30m
      • 15:45
        Holographic aspects of loop quantum gravity 1h 15m
        Speaker: Dr Norbert Bodendorfer (University of Regensburg)
        Slides
    • 09:30 12:30
      Session 3
      • 09:30
        The non-perturbative phase diagram of the BMN matrix model 1h 15m
        We study the maximally supersymmetric plane wave matrix model (the BMN model) at finite temperature, T, and locate the leading phase boundary as the temperature is lowered.
        Speaker: Dr Denjoe O'Connor (Dublin IAS)
        Slides
      • 10:45
        Coffee break 30m
      • 11:15
        Supersymmetry gradient flow 1h 15m
        Speaker: Dr Daisuke Kadoh (Keio University)
        Slides
    • 12:30 14:00
      Lunch & discussions
    • 14:00 17:00
      Session 4
      • 14:00
        Lattice quantum gravity and asymptotic safety 1h 15m
        Speaker: Dr Jack Laiho (Syracuse University)
        Slides
      • 15:15
        Coffee break 30m
      • 15:45
        Spectral Methods in Causal Dynamical Triangulations 1h 15m
        I will discuss the application of spectral analysis, i.e. analysis of the spectrum and eigenvectors of the Laplace-Beltrami operator, in the setting of the Monte-Carlo approach to Quantum Gravity called Causal Dynamical Triangulations (CDT). In particular, applying the method to the analysis of spatial slices shows that the different phases can be characterized by a new order parameter related to the presence or absence of a gap in the spectrum of the Laplace-Beltrami operator, and allows to derive an effective dimensionality of the slices at different scales.
        Speaker: Dr Giuseppe Clemente (Pisa University)
        Paper
        Slides
    • 09:30 12:30
      Session 5
      • 09:30
        Anomalous dimensions in conformal systems: non-perturbative gradient flow approach 1h 15m
        Speaker: Dr Anna Hasenfratz (University of Colorado)
        Slides
      • 10:45
        Coffee break 30m
      • 11:15
        Hierarchies, dynamical supersymmetry breaking & holographic duality 1h 15m
        Speaker: Dr Joel Giedt (Rensselaer)
        Paper
        Slides
    • 12:30 14:00
      Lunch & discussions
    • 14:00 17:00
      Session 6
      • 14:00
        Extreme Holography 1h 15m
        A massive experimental effort will be devoted in the coming years to the physics of QCD at high energy density and/or high baryon density. Understanding this physics, especially out of equilibrium, is an important theoretical challenge. I will discuss how holography can help us address this challenge. Topics covered will include the far-from-equilibrium dynamics near the QCD critical point and colour superconducting phases. No prior knowledge of string theory required.
        Speaker: Dr David Mateos (University of Barcelona)
      • 15:15
        Coffee break 30m
      • 15:45
        The physics of non-hydrodynamic modes 1h 15m
        Speaker: Dr Paul Romatschke (University of Colorado)
        Slides
    • 09:30 12:30
      Session 7
      • 09:30
        Probing D0-brane Black Holes 1h 15m
        Speaker: Dr Evan Berkowitz (FZ Juelich)
        Slides
      • 10:45
        Coffee break 30m
      • 11:15
        Supersymmetry and conformal theories on the lattice, from super Yang-Mills towards super QCD 1h 15m
        Speaker: Dr Georg Bergner (Jena University)
    • 12:30 14:00
      Lunch & discussions
    • 14:00 17:00
      Session 8
      • 14:00
        Holographic Lattice Cosmology 1h 15m
        Speaker: Dr Kostas Skenderis (University of Southampton)
        Slides
      • 15:15
        Coffee break 30m
      • 15:45
        Dynamical generation of 4d space-time in nonperturbative superstring theory 1h 15m
        We discuss our numerical work on the IKKT matrix model, which was conjectured to be a nonperturbative formulation of superstring theory. In particular, we focus on its Euclidean version, which is speculated to undergo an SSB of SO(10) rotational symmetry, corresponding to the dynamical generation of 4d space-time, due to the effects of the complex fermion determinant. While this issue is difficult to study by conventional Monte Carlo methods because of the sign problem, we show that the complex Langevin method can give clear answers. After discussing important recent developments concerning this method, we present explicit results for some simplified matrix models as well as preliminary results for the original IKKT model. Ref.) JHEP 1802 (2018) 151 [arXiv:1712.07562 [hep-lat]]
        Speaker: Dr Jun Nishimura (KEK)
        Slides