2019 Workshop
Workshop on holography, gauge theories and black holes
STAG Research Centre, Southampton University,
24 - 25 June 2019
Invited Speakers:
- Samuel Abreu - (Edinburgh)
- Arjun Bagchi - (IIT Kanpur)
- Agnese Bissi - (Uppsala)
- Blaise Gouteraux - (CPHT, Ecole Polytechnique)
- Charlotte Kristjansen - (NBI, Copenhagen)
- Sameer Murthy - (KCL)
- Carlos Nunez- (Swansea)
- Ioannis Papadimitriou - (KIAS)
- Chiara Toldo - (CPHT, Ecole Polytechnique)
- Nicholas Warner - (USC)
Organisers:
Ines Aniceto, Oscar Dias, James Drummond, Nick Evans, Masanori Hanada, Carlos Mafra, Andy O'Bannon, Brandon Robinson, Kostas Skenderis, Marika Taylor and David Turton
Venue:
Talks' Timetable:
Titles and Abstracts:
Speaker: Samuel Abreau
Title: Two-loop multi-leg amplitudes from numerical unitarity
Abstract: I will discuss the recent calculation of several five-point amplitudes relevant for phenomenological studies at hadron colliders in the framework of two-loop numerical unitarity. Combined with analytic reconstruction techniques, numerical unitarity can be used to extract analytic expressions for these amplitudes. Physical constraints allow to simplify these expressions and obtain very compact results.
Speaker: Arjun Bagchi
Title: BMS Modular Invariance and Characters
Abstract: In this talk, we will consider 2d field theories invariant under the BMS algebra, putatively dual to 3d Minkowski spacetimes and discuss the notion of a version of modular invariance in these theories. We will revisit the derivation of the BMS-Cardy formula and its reproduction of the entropy of cosmological horizons in flat space. We would then discuss in detail the construction of highest weight characters for these 2d field theories and point out a rather remarkable matching to characters of the very different induced representations.
Speaker: Agnese Bissi
Title: Genus one string amplitudes from CFT
Abstract: In this talk I will present how to use analytic methods of the conformal bootstrap to construct non-planar correlators in N = 4 super-Yang-Mills and to relate them to detailed features of perturbative type II closed string amplitudes. In particular, I will discuss how to construct the one-loop/genus-one, four-point string amplitude in AdS_5 × S^5 in the low-energy expansion, holographically dual to the N = 4 SYM four-point function of the half-BPS operator, in the ‘t Hooft limit at O(1/N^2) and in a strong coupling expansion.
Speaker: Blaise Gouteraux
Title: Transport and holographic density waves
Abstract: In this talk, I will review recent progress on computing transport properties of holographic phases breaking translations spontaneously, and discuss how this matches to the corresponding effective theory of density wave hydrodynamics. This EFT differs from fluid hydrodynamics by the presence of additional gapless modes, the Goldstones of the spontaneously broken symmetry, which couple to the usual conserved densities. After introducing a small source of explicit translation symmetry breaking, the Goldstones become gapped with a small mass and damping rate. These quantities can be computed holographically. Plugging this in the expressions for the collective modes predicted by the EFT leads to excellent agreement with the longest-lived Quasi-Normal Modes of the dual black hole. I will close by commenting on how a coupling between the Goldstone and the conserved currents leads to universal expressions for the relaxation parameters, as well as the relevance of these results for various strongly-correlated materials.
Speaker: Charlotte Kristjansen
Title: One-point functions in AdS/dCFT with and without supersymmetry
Abstract: We review recent results on the calculation of one-point functions in dCFTs corresponding to N=4 SYM with domain walls, discussing supersymmetric as well as non-supersymmetric cases. In particular, we address the integrability properties of the theories and the status of the comparison to dual string theoretical computations.
Speaker: Sameer Murthy
Title: The asymptotic growth of states of the 4d superconformal index and supersymmetric AdS5 black holes
Abstract: It was thought until recently that the most general 4d superconformal index on $S^3 \times S^1$ does not contain an exponential growth of states as a function of the charges, thus posing the puzzle: how do we account for the entropy of supersymmetric black holes in the holographically dual AdS_5? I will discuss recent progress on this subject showing that the superconformal index does indeed have an exponential growth of states which is completely consistent with the existence of a black hole. I will discuss this from both the bulk and boundary point of view. This will be based on arXiv:1810.11442, arXiv:1904.05865, and some work in progress.
Speaker: Carlos Nuñez
Title: Aspects of gauge-gravity duality
Abstract: I discuss recent developments in the correspondence between gauge fields and strings. In particular, I will discuss the case of conformal field theories in diverse dimensions and with different amounts of supersymmetry. Physical observables will be calculated and a relation with integrability discussed.
Speaker: Ioannis Papadimitriou
Title: Supersymmetric Anomalies
Abstract: The Wess-Zumino consistency conditions for supersymmetric quantum field theories with an anomalous flavor or R-symmetry imply the existence of a supersymmetry anomaly, i.e. a non vanishing divergence for the supercurrent in the presence of fermionic sources for the flavor or current multiplets. I will discuss how this anomaly affects the supersymmetric partition function on backgrounds admitting rigid supersymmetry and outline other implications.
Speaker: Chiara Toldo
Title: Filling the boundary: NUTs and Bolts of AdS holography
Abstract: The partition function of SCFTs on 3d manifolds such as product manifolds and circle bundles of closed 2d Riemann surfaces was recently computed via supersymmetric localization. In this talk I will present supergravity solutions having as conformal boundary such manifolds. I will start with the simple case where the boundary is a direct product and I will discuss its relevance for black hole micro state counting in AdS4. Then I will describe solutions having as boundary a circle bundle (AdS-Taub-NUT and AdS-Taub-Bolt) and I will show the matching of their on-shell action with the large N limit of the partition function of the dual CFT. I will finally discuss some recent results for a third and more challenging example, which involves the refinement by angular momentum.
Accomodation: