## 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)

### 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.

### 30.11.2016 (Wednesday)

#### AdS4 black holes and 3d gauge theories

Regular Seminar Alberto Zaffaroni (Milan Bicocca)

 at: 13:15 KCLroom G01 Norfolk Building abstract: One of the great success of string theory is the microscopical explanation of the entropy of a class of asymptotically flat black holes. Much less is known about asymptotically AdS black holes in four dimensions or higher. In this talk I explain how to derive the entropy of a class of asymptotically AdS supersymmetric black holes in four dimensions using holography. The counting of black hole micro-states is related to a counting of states in the dual 3d gauge theory which can be explicitly performed using localization.

### 23.11.2016 (Wednesday)

#### Non-Wilsonian RG flows and the T barT perturbation of 2D quantum field theories

Regular Seminar Roberto Tateo (University of Turin)

 at: 13:15 KCLroom G01 Norfolk Building abstract: An interesting link between the effective string theory describing the colour confinement in Yang-Mills theories and conformal field theories perturbed by the composite operator $T \bar{T}$ was recently discovered. We will discuss various aspects of this special kind of integrable perturbation and how it affects the energy levels of a generic 2D Quantum Field Theory, through a surprising relation with the inviscid Burgers equation. As this class of models corresponds to non-Wilsonian RG trajectories, these studies may help to clarify important aspects concerning the appearance of singularities in effective QFT, and hopefully be useful in the effective string framework.

### 16.11.2016 (Wednesday)

#### Vertex operator algebras from four-dimensional SCFTs

Regular Seminar Christopher Beem (Oxford University)

 at: 13:15 KCLroom G01 Norfolk Building abstract: I will review the recently exposed connection between N=2 superconformal field theories in four dimensions and vertex operator algebras (VOAs). I will outline some general features of the VOAs that arise in this manner and describe the manner in which they reflect four-dimensional operations such as gauging and Higgsing. Time permitting, I will also touch on the modular properties of characters of these VOAs.

### 09.11.2016 (Wednesday)

#### An algebraic approach to the classification of supergravity backgrounds

Regular Seminar Jose Miguel Figueroa-O'Farrill (Edinburgh)

 at: 13:15 KCLroom G01 Norfolk Building abstract: I will report on joint work with Andrea Santi outlining an algebraic reformulation of the classification problem of eleven-dimensional supergravity backgrounds. The basic object of study is the Killing superalgebra of the background, whose algebraic structure has recently been elucidated. If time permits I will also comment on work also involving Paul de Medeiros applying these techniques to the construction of rigidly supersymmetric theories in curved spaces.

### 26.10.2016 (Wednesday)

#### Supersymmetric Localization on AdS2 x S1

Regular Seminar Rajesh Gupta (King's College London)

 at: 13:15 KCLroom G01 Norfolk Building abstract: Conformal symmetry relates the metric on AdS_2 x S^1 to that of S^3. This implies that under a suitable choice of boundary conditions for fields on AdS_2 the partition function of conformal field theories on these spaces must agree which makes AdS_2 \times S^1 a good testing ground to study supersymmetric localization on non-compact spaces. We evaluate the partition function of N=2 supersymmetric Chern-Simons theory on AdS_2 x S^1 using localization, where the radius of S^1 is q times that of AdS_2. With boundary conditions on AdS_2 x S^1 which ensure that all the physical fields are normalizable and lie in the space of square integrable wave functions in AdS_2, we find that the result for the partition function precisely agrees with that of the theory on the q-fold covering of S^3.

### 19.10.2016 (Wednesday)

#### Comments on the Space of QFTs

Regular Seminar Matthew Buican (Queen Mary University of London)

 at: 13:15 KCLroom G01 Norfolk Building abstract: In the first part of the talk, I will revisit the question of how to decide whether two 4D N=2 superconformal field theories describe the same physics. Time permitting, I will discuss related questions regarding the classification of 2D rational conformal field theories.

### 12.10.2016 (Wednesday)

#### Vortices and Vermas

Regular Seminar Matthew Bullimore (Oxford University)

 at: 13:15 KCLroom G01 Norfolk Building abstract: In 3d gauge theories, monopole operators create and destroy vortices. I will explore this idea in the context of 3d supersymmetric gauge theories in the presence of an omega background, and explain how it leads to a finite version of the AGT correspondence.

### 05.10.2016 (Wednesday)

#### An operator for the zeros of the Riemann zeta function

Regular Seminar Brody Dorje (Imperial College)

 at: 13:15 KCLroom G01 Norfolk Building abstract: The Riemann hypothesis asserts that the nontrivial zeros of the Riemann zeta function should be of the form 1/2 + i E_n, where the set of numbers {E_n} are real. The so-called Hilbert-PÃ³lya conjecture assumes that {E_n} should correspond to the eigenvalues of an operator that is Hermitian. The discovery of such an operator, if it exists, thus amounts to providing a proof of the Riemann hypothesis. In 1999 Berry and Keating conjectured that such an operator should correspond to a quantisation of the classical Hamiltonian H = xp. Since then, the Berry-Keating conjecture has been investigated intensely in the literature, but its validity has remained elusive up to now. In this talk I will derive a "Hamiltonian" (a differential operator), whose classical counterpart is H = xp, having the property that with a suitable boundary condition on its eigenstates, the eigenvalues {E_n} correspond to the nontrivial zeros of the Riemann zeta function. This Hamiltonian is not Hermitian, but is symmetric under space-time reflection (PT symmetric) in a special way. A formal argument will be given for the construction of the metric operator to define an inner-product space for the eigenstates, and the formally "Hermitian" counterpart Hamiltonian. The talk is based on the work carried out in collaboration with Carl M. Bender (Washington University) and Markus P. Mueller (University of Western Ontario).

### 07.09.2016 (Wednesday)

#### Kounterterms in AdS Gravity

Exceptional Seminar Rodrigo Olea Aceituno (UNAB, Chile)

 at: 13:15 KCLroom S5.20 abstract: As an alternative to the Holographic Renormalization procedure in the context of AdS/CFT correspondence, we introduce a regularization scheme for AdS gravity based on the addition of boundary terms which are a given polynomial of the extrinsic and intrinsic curvatures (Kounterterms). These terms are closely related to either topological invariants or Chern-Simons densities in the corresponding dimension, they can be easily generalized to other gravity theories (Einstein-Gauss-Bonnet, Lovelock, etc.). We provide a general prescription on how to obtain standard holographic quantities at the boundary. We also briefly comment on a possible relation to supersymmetry.

### 29.08.2016 (Monday)

#### STiL 2016: Supersymmetry, Geometry, and Holography

Exceptional Seminar - - (-)

 at: 10:00 KCLroom tba abstract: 29 August - 3 September, King's College London. This workshop intends to bring together leading experts and young researchers working on the broad themes of quantum field theory, black holes and gravitation, and holography, so as to share new ideas, calculations, and results in a focused setting. The topics covered in the workshop include: Symmetries and dualities in field theory and gravity Classical and quantum aspects of black holes Supersymmetric localization and exact results Mathematical aspects of string theory Supergravity solutions and holography Website Registration will be closed on 8 July 2016 or when positions are filled.

### 28.04.2016 (Thursday)

#### Towards a theory of gravitational radiation

Exceptional Seminar Pawel Nurowski (Centre for Theoretical Physics, Polish Academy of Sciences, Warsaw, Poland)

 at: 16:00 KCLroom K2.3, Nash Lecture theatre abstract: The recent observation of gravitational waves by LIGO has revived interest in the work on the theory of gravitational radiation done at King's and elsewhere in the 1950's and early 60's. It is well known that after predicting gravitational waves in 1916 Einstein became uncertain about their physical reality. It wasn't until the 1950's and early 60's that their physical status was clarified. Important contributions to the development of the theory of gravitational radiation were made at this time by members of the King's relativity group such as Hermann Bondi, Felix Pirani and Roger Penrose. In 1958 Andrzej Trautman from Leopold Infeld's relativity group in Warsaw delivered a series of highly influential lectures on gravitational radiation at King's. In this talk the work of the Warsaw group, and Trautman in particular, will be discussed and its influence on the development of gravitational wave theory will be explained. Refreshments will be available after the lecture. Please RSVP to: D C Robinson david.c.robinson@kcl.ac.uk

### 30.03.2016 (Wednesday)

#### On Killing superalgebras and filtered deformations

Exceptional Seminar Andrea Santi (University of Edinburgh, Marie-Curie INdAM)

 at: 13:15 KCLroom K4.31 abstract: I will present ongoing work with J. Figueroa-O’Farrill and P. de Medeiros on the algebraic structure of Lie superalgebras $g = g_0 \oplus g_1$ generated by Killing spinors. I will explain how any $g$ can be regarded as an appropriate deformation of a subalgebra of the Poincaré superalgebra and discuss applications to the classification of supersymmetric supergravity backgrounds and the geometries admitting rigidly supersymmetric field theories.

### 23.03.2016 (Wednesday)

#### Opers and the E6 Minahan-Nemeschansky theory

Regular Seminar Lotte Hollands (Heriot-Watt U., Edinburgh)

 at: 13:15 KCLroom K4.31 abstract: In this seminar I explain a geometric proposal to determine a nonperturbative partition function for the E6 Minahan-Nemeschansky theory. Important ingredients are generating functions of opers, spectral networks and a generalisation of complex Fenchel-Nielsen coordinates to moduli spaces of higher rank flat connections. (This is joint work with Andy Neitzke.)

### 16.03.2016 (Wednesday)

#### Prethermalization and thermalization in models with weak integrability breaking

Regular Seminar Fabian Essler (Oxford U.)

 at: 13:15 KCLroom K4.31 abstract: I consider the the effect of weak integrability breaking interactions on the non-equilibrium time evolution in many-particle systems. Using a class of weakly interaction fermion models as an example, I argue that there exists a time window in which the system relaxes locally to a non-equilibrium meta-stable state, before it eventually thermalizes.