Directions

This institute may be found at Strand in Central London, just north of the Thames (map).

Getting to the Strand Campus:

• By underground

Temple (District and Circle lines): 2 minute walk. Charing Cross (Bakerloo and Northern lines): 10 minute walk, Embankment (District, Circle and Bakerloo lines): 10 minute walk, Waterloo (Jubilee, Northern, Bakerloo, Waterloo & City lines): 12 minute walk, Holborn (Central and Picadilly lines): 12 minute walk,Chancery Lane (Central line): use exit 4 - 15 minute walk.

• By train

Charing Cross: 9 minute walk. Waterloo: 12 minute walk. Waterloo East: 10 minute walk. Blackfriars: 12 minute walk.

• By bus

Buses stopping outside the College: 1, 4, 26, 59, 68, 76, X68, 168, 171, 172, 176(24 hour), 188, 243 (24 hour), 341 (24 hour), 521, RV1.

Seminars at King's College London

Found at least 20 result(s)

15.11.2017 (Wednesday)

Black Hole Microstates in String Theory

Regular Seminar David Turton (Southampton University)

 at: 13:15 KCLroom K4.31 abstract: The Information Paradox represents a strong consistency challenge for any quantum theory of gravity. The study of black hole internal structure in String Theory offers the potential to resolve this paradox. I will give an overview of recent work on constructing families of smooth horizonless supergravity solutions describing black hole microstates. Where applicable, I will present a holographic description of these solutions. I will also discuss the physics of an observer falling into a black hole.

08.11.2017 (Wednesday)

Twisted BRST quantization and localization in supergravity

Regular Seminar Sameer Murthy (King's College London)

 at: 13:15 KCLroom K4.31 abstract: Supersymmetric localization is a powerful technique to evaluate a class of functional integrals in supersymmetric field theories. It reduces the functional integral over field space to ordinary integrals over the space of solutions of the off-shell BPS equations. The application of this technique to supergravity suffers from some problems, both conceptual and practical. I will discuss one of the main conceptual problems, namely how to construct the fermionic symmetry with which to localize. I will show how a deformation of the BRST technique allows us to do this. I will then sketch a computation of the one-loop determinant of the super-graviton that enters the localization formula for BPS black hole entropy.

03.11.2017 (Friday)

King's Journal Club

Journal Club Chris Couzens (King's College)

 at: 16:00 KCLroom S4.23 abstract: Review of 1710.03934v1

27.10.2017 (Friday)

King's Journal Club

Journal Club Rajesh Gupta (KCL)

 at: 16:00 KCLroom S4.23 abstract: We will discuss "From 3d duality to 2d duality" https://arxiv.org/abs/1710.00926 by Aharony, Razamat and Willett.

25.10.2017 (Wednesday)

Chiral Algebras for four dimensional N=4 SCFT

Regular Seminar Carlo Meneghelli (Oxford)

 at: 13:15 KCLroom K4.31 abstract: Any four dimensional N=2 superconformal field theory (SCFT) contains a subsector of local operator which is isomorphic to a two dimensional chiral algebra. If the 4d theory possesses N=3 or N= 4 superconformal symmetry, the corresponding chiral algebra is an extension the N=2 or (small) N=4 super-Virasoro algebra respectively. In this talk I will present some results on the classification of N=4 chiral algebras and discuss if they can correspond to a 4d theory.

18.10.2017 (Wednesday)

On the exact interpolating function in ABJ theory

Regular Seminar Andrea Cavaglia (KCL)

 at: 13:15 KCLroom K4.31 abstract: I will discuss integrability in the context of planar AdS4/CFT3, where the CFT is the so-called ABJ model depending on two t'Hooft couplings. When the two couplings are equal, this reduces to the ABJM theory, whose integrable structure is well understood but depends on an unspecified interpolating function of the coupling. I will motivate a proposal that the most general ABJ case is also integrable, and that the two coupling constants l1 and l2 recombine into a single interpolating function h( l1 , l2 ) , so that the spectrum is a function of h only. Extending and idea by N. Gromov and G. Sizov on the ABJM case, an explicit conjecture for the form of h(l1, l2) wil be made, based on the comparison between integrability and localization results. The talk is based on the paper hep-th/1605.04888 with N. Gromov and F. Levkovich-Maslyuk.

04.10.2017 (Wednesday)

The topologically twisted index on H2xS1 and its relation to the entropy of hyperbolic AdS4 black holes.

Regular Seminar Alejandro Cabo-Bizet (KCL)

 at: 13:15 KCLroom K4.31 abstract: I will start by sketching the computation of the topologically twisted index on H2xS1 and its evaluation in ABJM theory in the large N limit with k=1. Then after, I will review the key points behind the construction of magnetically charged (hyperbolic) AdS4 black holes on STU gauged SUGRA and will conclude by stating how the aformentioned index -- upon extremization -- coincides with the entropy of the latter black holes in the large N limit (with k=1).

27.09.2017 (Wednesday)

Segmented strings

Regular Seminar David Vegh (QMUL)

 at: 13:15 KCLroom Segmented strings abstract: The goal of this talk is twofold. Firstly, I would like to popularize the segmented string approach for solving the classical string dynamics on certain symmetric spacetimes where the string motion is integrable. This allows for an exact discretization which renders the equation of motion discrete in both space and time. The corresponding string solution is a segmented string. I will review the properties of segmented strings and relate them to discrete-time Toda-type lattices. The second goal of the talk is to understand a concrete setup: a (segmented) string hanging from the boundary of three-dimensional AdS spacetime. According to the gauge/gravity duality, the string in the bulk is dual to a flux tube between a quark-antiquark pair in the boundary field theory. We assume that the string is initially (quasi-)static. Perturbing one of the endpoints creates a large propagating wave on the string. The non-linear time-evolution produces a number of interesting phenomena: energy cascades, pair-creation of cusps, and evaporating regions on the string. If time permits, I will also talk about the string worldsheet as a simple model for gravity, chaos, out-of-time-order four-point functions, and segmented membranes.

12.05.2017 (Friday)

Module classification in conformal field theory through symmetric polynomials

Exceptional Seminar Simon Wood (Cardiff)

 at: 15:00 KCLroom S4.29 abstract: Given some chiral conformal field theory (also known as a vertex operator algebra in the mathematics literature), a natural but highly non-trivial task is to classify its representation theory. In this talk, I will use some well known examples of conformal field theories, such as the Virasoro minimal models, to show how certain hard questions in representation theory can be neatly rephrased as comparatively easy questions in the theory of symmetric polynomials. After a brief overview of the theory of symmetric polynomials, I will show how they can be used to classify irreducible representations.

29.03.2017 (Wednesday)

Extended Riemannian Geometry and Double Field Theory

Regular Seminar Christian Samann (Heriot Watt University)

 at: 13:15 KCLroom G01 Norfolk Building abstract: I present an extended version of Riemannian geometry suitable for the description of current formulations of double field theory (DFT). This framework is based on graded manifolds and it yields extended notions of symmetries, dynamical data and constraints. In special cases, we recover general relativity with and without 1-, 2- and 3-form gauge potentials as well as DFT. We believe that our extended Riemannian geometry helps to clarify the role of various constructions in DFT. For example, it leads to a covariant form of the strong section condition. Furthermore, it should provide a useful step towards global and coordinate invariant descriptions of T- and U-duality invariant field theories.

22.03.2017 (Wednesday)

Polygon Seminar: Tree-level scattering amplitudes with the pure spinor formalism

Triangular Seminar Carlos Mafra (U. Southampton)

 at: 15:00 KCLroom S-1.27 floor minus 1 abstract: I will give a pedagogical review of how the pure spinor formalism was used to obtain all tree-level amplitudes of the superstring, including all their alpha' corrections.

22.03.2017 (Wednesday)

Resurgence in Large N Gauge and String Theory

Regular Seminar Ricardo Schiappa (Lisbon University)

 at: 13:15 KCLroom G01 Norfolk Building abstract: I will present a light introduction to resurgence, with applications in large N gauge theory and in string theory.

08.03.2017 (Wednesday)

Orbifolds and defects

Regular Seminar Ingo Runkel (Hamburg University)

 at: 13:15 KCLroom G01 Norfolk Building abstract:

22.02.2017 (Wednesday)

T-duality and the Gerbe in C-spaces

Regular Seminar Georgios Papadopoulos (King's College London)

 at: 13:15 KCLroom G01 Norfolk Building abstract: I shall review proposals that have been made to patch doubled spaces and explain the difficulties that arise in an effort to achieve consistent patching. Then I shall propose a scheme based on C-spaces that leads to a consistent patching but requires additional coordinates to those of doubled spaces. The T-dual pairs are identified as subspaces of the gerbe in C-spaces. The talk is based on work done with Paul Howe, arXiv:1612.07968 [hep-th].

15.02.2017 (Wednesday)

RG boundaries and interfaces in Ising field theory

Regular Seminar Anatoly Konechny (Heriot Watt University)

 at: 13:15 KCLroom G01 Norfolk Building abstract: Perturbing a CFT by a relevant operator on a half space and letting the perturbation flow to the far infrared we obtain an RG interface between the UV and IR CFTs. If the IR CFT is trivial we obtain an RG boundary condition. The space of massive perturbations thus breaks up into regions labelled by conformal boundary conditions of the UV fixed point. For the 2D critical Ising model perturbed by a generic relevant operator we find the assignment of RG boundary conditions to all flows. We use some analytic results but mostly rely on TCSA and TFFSA numerical techniques. We investigate real as well as imaginary values of the magnetic field and, in particular, the RG trajectory that ends at the Yang-Lee CFT. We argue that the RG interface in the latter case does not approach a single conformal interface but rather exhibits oscillatory non-convergent behaviour.

08.02.2017 (Wednesday)

Integrable quantum field theories and von Neumann algebras

Regular Seminar Gandalf Lechner (Cardiff University)

 at: 13:15 KCLroom G01 Norfolk Building abstract: In this talk, I will report on a research programme that addresses the problem of constructing integrable relativistic quantum field theories on two-dimensional Minkowski space from their two-body S-matrix. The aims of this programme are thus identical to the form factor programme, but the tools are different: Instead of concentrating on a perturbative construction of the correlation functions of local fields, we construct a pair of "semi-local" quantum fields and use operator-algebraic tools to study local fields/observables. This leads to a construction of many models, including the Sinh-Gordon model. As another prominent example, I will also report on the status of the O(N) sigma models within this setting.

25.01.2017 (Wednesday)

AdS crunches from relevant deformations of CFTs

Regular Seminar Prem Kumar (Swansea)

 at: 13:15 KCLroom G01 Norfolk Building abstract: We discuss examples of relevant deformations of known CFTs placed in de Sitter spacetime, possessing AdS gravity duals with Big Crunch singularities. We point out generic aspects of such dual backgrounds, including the behaviour in the vicinity of the singularity, holographic correlators in the geodesic approximation, and retarded correlators in an analytically tractable example within the AdS_4/CFT_3 context. We briefly describe an attempt to characterise the bulk crunch and its putative resolution within the O(N) vector model in 3D.

18.01.2017 (Wednesday)

Space-time CFTs from the Riemann sphere

Regular Seminar Tim Adamo (Imperial College)

 at: 13:15 KCLroom G01 Norfolk Building abstract: In recent years, there has been significant process in the study of perturbative field theory scattering amplitudes using certain 2d chiral, first-order CFTs known as 'ambitwistor string theories.' After a brief review of the ambitwistor setup, I will introduce a related family of 2d CFTs, which can be viewed as constrained ambitwistor strings. These new models describe holomorphic maps from the Riemann sphere to the projective null cone in D-dimensional Minkowski space. This target space is the natural setting to describe field theories with (classical) conformal invariance in (D-2)-dimensions. Killing the anomalies associated with these models fixes critical dimensions for which three well-known space-time field theories (bi-adjoint cubic scalar, gauge theory, gravity) are conformal. Furthermore, the spectrum of each model contains all single field insertions, along with their conformal descendants, of the correct scaling dimension. Time permitting, I will also outline how the space-time 3-point functions can be obtained from the 3-point correlators on the Riemann sphere.

07.12.2016 (Wednesday)

Examples of Berry phase in quantum field theory

Triangular Seminar Vasileios Niarchos (Durham)

 at: 15:00 KCLroom S-1.06 STRAND BLDG abstract: Berry phase is a well-known feature of quantum mechanics. In this talk I will discuss the less-explored subject of Berry phase in quantum field theory. We will see that even simple quantum field theories can exhibit non-trivial Berry phases, and will discuss an explicit example in axion electrodynamics. We will also discuss a general relation between the Berry connection in conformal field theories with non-trivial conformal manifolds and the connections previously considered by several authors in conformal perturbation theory. The implementation of this relation in 2d N=(2,2) and 4d N=2 superconformal field theories leads to a useful re-derivation of the tt* equations.

07.12.2016 (Wednesday)

Superstring worldsheet in AdS/CFT: beyond perturbation theory

Triangular Seminar Valentina Forini (Humboldt, Berlin)

 at: 16:30 KCLroom S-1.06 STRAND BLDG at KCL abstract: String sigma-models relevant in AdS/CFT are highly non-trivial two-dimensional field theories for which predictions at finite coupling assume integrability and/or the duality itself. In this framework, I will discuss progress on how to extract finite coupling information via the use of lattice field theory methods.