This institute may be found at Strand in Central London, just north of the Thames (map).
Getting to the Strand Campus:
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.
Charing Cross: 9 minute walk. Waterloo: 12 minute walk. Waterloo East: 10 minute walk. Blackfriars: 12 minute walk.
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.
For more information about public transportations in London, please visit http://www.tfl.gov.uk.
Found at least 20 result(s)
Exceptional Seminar Claire Zukowski (University of Amsterdam)
at: 15:45 room Norfolk Building G.01 | abstract: TBA |
Triangular Seminar Shota Komatsu (CERN)
at: 14:30 room online | abstract: I will discuss the fundamentals of quantum field theory on a rigid de Sitter space. First, I will show that the perturbative expansion of late-time correlation functions to all orders can be equivalently generated by a non-unitary Lagrangian on a Euclidean AdS geometry. This finding simplifies dramatically perturbative computations, as well as allows us to establish basic properties of these correlators, which comprise a Euclidean CFT. Second, I use this to infer the analytic structure of the spectral density that captures the conformal partial wave expansion of a late-time four-point function, to derive an OPE expansion, and to constrain the operator spectrum. Third, I will prove that unitarity of the de Sitter theory manifests itself as the positivity of the spectral density. This statement does not rely on the use of Euclidean AdS Lagrangians and holds non-perturbatively. |
Triangular Seminar Shota Komatsu (CERN)
at: 16:00 room online | abstract: I will discuss two topics on the large charge limit and holography. First, I will discuss general features of the large-charge limit of superconformal field theories at large N. In particular, I will point out a simple setup to analyze the large charge expansion of the planar N=4 super Yang-Mills and discuss its holographic interpretation. Second, I will discuss the large-charge limit of the defect CFT on the Wilson line and its relation to the matrix model. |
Regular Seminar Chris Herzog (KCL)
at: 10:30 room Online | abstract: Lonti Autumn 2021 Series: Lecture 1. Live Tutorial. Please register at https://lonti.weebly.com/registration.html to receive joining instructions for this live session which will be held via Zoom. Four examples of an anomaly are presented, two from quantum mechanics and two from quantum field theory. The first example is a charged bead on a wire in the presence of a magnetic field. This example of a 't Hooft anomaly is related to the theta angle in Yang-Mills theory. The remaining three examples present scale and conformal anomalies. We will scatter a plane wave off an attractive delta function in two dimensions. We also look at a massless scalar field, both in two dimensions without a boundary and in three dimensions with one. |
Regular Seminar Avia Raviv-Moshe (Stony Brook U., New York, SCGP)
at: 15:45 room Online | abstract: In this talk, we will consider line defects in d-dimensional CFTs. The ambient CFT places nontrivial constraints on renormalization group flows on such line defects. We will see that the flow on line defects is consequently irreversible and furthermore a canonical decreasing entropy function exists. This construction generalizes the g theorem to line defects in arbitrary dimensions. We will demonstrate this generalization in some concrete examples, including a flow between Wilson loops in 4 dimensions, and an O(3) bosonic theory coupled to impurities with large isospin. |
Regular Seminar Chris Herzog (KCL)
at: 10:00 room Youtube | abstract: Lonti Autumn 2021 Series: Lecture 1. Release of Recorded Lecture. Available here: https://youtu.be/hiUnq_5iiPM. Four examples of an anomaly are presented, two from quantum mechanics and two from quantum field theory. The first example is a charged bead on a wire in the presence of a magnetic field. This example of a 't Hooft anomaly is related to the theta angle in Yang-Mills theory. The remaining three examples present scale and conformal anomalies. We will scatter a plane wave off an attractive delta function in two dimensions. We also look at a massless scalar field, both in two dimensions without a boundary and in three dimensions with one. |
Regular Seminar Paul Ryan (KCL / Trinity College Dublin)
at: 13:45 room K0.20 | abstract: The spectral problem for N=4 Super Yang-Mills can be formulated as a set of quantisation conditions on a handful of functions called Q-functions. Recent analysis suggests that the Q-functions can be used as simple building blocks for 3-point correlation functions. This strongly resembles the situation in integrable spin chains where the wave functions factorise into a simple product of Q-functions in a special basis called Sklyaninâ€™s separation of variables (SoV) basis which is one of the most powerful approaches for solving integrable systems. Unfortunately this framework has only been developed for the simplest integrable spin chains with sl(2) symmetry, far from the psu(2,2|4) needed to describe N=4 SYM. In this talk I will review recent advances in developing the SoV approach for higher rank integrable spin chains. I will explain how to construct the SoV basis in a systematic fashion and how it links to the representation theory of the system. Next, I will discuss a new approach for obtaining the measure in separated variables based on the famous Baxter TQ equation and how the approach naturally provides a large family of correlation functions as very simple determinants in Q-functions. I will briefly discuss how the approach can be applied directly to certain 4d QFTs, in particular the fishnet cousin of N=4 SYM. |
Regular Seminar Pietro Benetti Genolini (KCL / Cambridge Univ. DAMTP)
at: 13:45 room K0.20 | abstract: Five-dimensional non-abelian gauge theories have a U(1) global symmetry associated with instantonic particles. I will describe a mixed 't Hooft anomaly between this and other global symmetries of the theory, namely the one-form center symmetry or ordinary flavor symmetry for theories with fundamental matter. I will then apply these results to supersymmetric gauge theories, analysing the symmetry enhancement patterns occurring at their conjectured RG fixed points. |
Regular Seminar Marco Serone (SISSA, INFN Trieste)
at: 13:45 room online | abstract: Four-dimensional gauge theories can flow in the IR to non-trivial CFTs. By employing Borel resummation techniques both to the ordinary perturbative series and to the Banks-Zaks conformal expansion, we first analyze the conformal window of QCD and find substantial evidence that QCD with n_f=12 flavours flows in the IR to a CFT. We then study UV fixed points for SU(n_c) gauge theories with fundamental fermion matter in 4+2epsilon dimensions. Using resummation techniques similar to those used in the 4d QCD case, we provide evidence for the existence of non-supersymmetric CFTs in d=5 space-time dimensions in a certain range of colors and flavours. |
Regular Seminar Luca Iliesiu (Stanford U.)
at: 13:45 room K2.31 | abstract: Understanding the fate of semi-classical black hole solutions at very late times is one of the most important open questions in quantum gravity. In this paper, we provide a path integral definition of the volume of the black hole interior and study it at arbitrarily late times for black holes in various models of two-dimensional gravity. Because of a novel universal cancellation between the contributions of the semi-classical black hole spectrum and some of its non-perturbative corrections, we find that, after a linear growth at early times, the length of the interior saturates at a time, and towards a value, that is exponentially large in the entropy of the black hole. This provides a non-perturbative confirmation of the complexity equals volume proposal since complexity is also expected to plateau at the same value and at the same time. |
Exceptional Seminar Mathew Bullimore (Durham University)
at: 15:00 room S0.03 | abstract: The aim of this talk is to give a mathematical definition of the superconformal index of 3d supersymmetric gauge theories. This can be computed exactly using supersymmetric localisation, leading to an explicit contour integral formula involving infinite q-Pochammer symbols. I will explain how this may be understood as the Witten index of a supersymmetric quantum mechanics, or index of a twisted Dirac operator on a certain infinite-dimensional space closely related to one introduced by Braverman-Finkelberg-Nakajima. |
Regular Seminar Xinan Zhou (Princeton U., CTP)
at: 13:45 room Zoom, See abstract | abstract: In this talk, I will discuss AdS super gluon scattering amplitudes in various spacetime dimensions. These amplitudes are dual to correlation functions in a variety of non-maximally supersymmetric CFTs, such as the 6d E-string theory, 5d Seiberg exceptional theories, etc. I will introduce a powerful method based on symmetries and consistency conditions, and show that it fixes all the infinitely many four-point amplitudes at tree level. I will also point out many interesting properties and structures of these amplitudes, which include the flat space limit, Parisi-Sourlas-like dimensional reduction, hidden conformal symmetry, and a color-kinematic duality in AdS. Along the way, I will also review some earlier progress and the relation with this work. I will conclude with a brief discussion of various open problems. [please email alejandro.cabo_bizet@kcl.ac.uk for the zoom link] |
Regular Seminar Andreas Stergiou (Los Alamos)
at: 15:45 room Zoom, See abstract | abstract: Renormalization group methods have been used for almost 50 years to obtain results for critical exponents of conformal field theories (CFTs), while relying on assumptions and approximations that are not rigorously justified. The agreement with experiments is good in many cases, e.g. the 3D Ising model, but disagreements between theory and experiment that have remained unresolved for decades also exist. This indicates that our understanding of critical phenomena may be incomplete. More recently, the numerical conformal bootstrap, a fully nonperturbative method, has proven to be very powerful in calculating critical exponents and other physical observables of CFTs. In this talk we will review the numerical conformal bootstrap method and discuss potential resolutions it has suggested for unsettled questions pertaining to critical phenomena in frustrated magnets and structural phase transitions. [please email alejandro.cabo_bizet@kcl.ac.uk for the zoom link] |