Notice: Undefined index: location:Other in /var/www/html/triangle.mth.kcl.ac.uk/html/golden/index.php on line 459

Notice: Undefined index: location:Other in /var/www/html/triangle.mth.kcl.ac.uk/html/golden/index.php on line 459

## Seminars at

Found at least 20 result(s)

### 10.12.2020 (Thursday)

#### t.b.a.

Journal Club Matthias Wilhelm (Niels Bohr Institute Copenhagen)

 at: 15:15 Otherroom Zoom, instructions in abstract abstract: t.b.a. ---- Part of London Integrability Journal Club. If you are a new participant, please register filling the form at integrability-london.weebly.com. The link will be emailed.

### 03.12.2020 (Thursday)

#### Phases of unitary matrix models and lattice QCD in two dimensions

Journal Club Jorge Russo (University of Barcelona)

 at: 15:15 Otherroom Zoom, instructions in abstract abstract: We investigate the different large N phases of a deformed Gross-Witten-Wadia U(N) matrix model. The deformation, which leads to a solvable model, corresponds to the addition of characteristic polynomial insertions and mimicks the one-loop determinant of fermion matter. In one version of the model, the GWW phase transition is smoothed out and it becomes a crossover. In another version, the phase transition occurs along a critical line in the two-dimensional parameter space spanned by the 't~Hooft coupling $\lambda$ and the Veneziano parameter $\tau$. A calculation of the $\beta$ function shows the existence of an IR stable fixed point. ---- Part of London Integrability Journal Club. If you are a new participant, please register filling the form at integrability-london.weebly.com. The link will be emailed.

### 26.11.2020 (Thursday)

#### Integrability Gong Show

Journal Club six speakers ( )

 at: 15:15 Otherroom Zoom, instructions in abstract abstract: This Thursday we will have six speakers presenting a 10 mins talk each. 1) Stefano Baiguera (Niels Bohr Institute), "Non-relativistic near-BPS corners of N=4 super Yang-Mills with SU(1,1) symmetry". 2) Ilija Buric (Desy), "From Integrable Gaudin Models to Multipoint Conformal Blocks", 3) Julius Julius (King's College London), "Baxter Equation for Boundary Integrability", 4) Rob Klabbers (Nordita), "How coordinate Bethe ansatz works for Inozemtsev model", 5) Yuan Miao (University of Amsterdam), "On the Q-operator and the spectrum of the XXZ model at root of unity". 6) Anne Spiering (Trinity College Dublin), "Integrability and Quantum Chaos in N=4 SYM from the Spectral Rigidity". Join us to hear the latest news in integrability! Important: Please make sure your Zoom version is updated, in order to use the break-out rooms feature for discussions after the talks. See the journal club website for abstracts of the talks. ----------------------------- Part of the London Integrability Journal Club. New participants please register using the form which can be found on the webpage integrability-london.weebly.com. The link will be emailed.

### 19.11.2020 (Thursday)

#### Integrable Kondo line defect, 4D Chern Simons, and ODE/IM correspondence

Journal Club Jingxiang Wu (Perimeter Institute)

 at: 15:15 Otherroom Zoom, instructions in abstract abstract: I will discuss the integrability and wall-crossing properties of Kondo line defects in rational conformal field theories. It provides a large class of interesting defect RG flow starting from topological line defects. As a surprise, I will discuss new examples of the ODE/IM correspondence and our attempts towards its physical origin using 4d Chern Simons theory. This work is part of a multi-pronged exploration of studying 4D Chern-Simons theory as an overarching structure for integrable systems. ---- Part of London Integrability Journal Club. New participants can register using the form at integrability-london.weebly.com. The link will be emailed.

### 16.11.2020 (Monday)

#### Witten diagrams and the Mellin transform in AdS/CFT

Journal Club Congkao Wen (QMUL)

 at: 09:00 Otherroom Online abstract: AdS/CFT duality (or more general holographic principle) represents a major advance in understanding quantum gravity, and provides powerful tools for studying strongly coupled quantum field theories. This talk will give a basic introduction to AdS/CFT duality, with the focus on the computation of Witten diagrams and their Mellin transform. Witten diagrams, which play the role of Feynman diagrams, provide the means for computing correlation functions in AdS/CFT. We will show that CFT correlation functions obtained from Witten diagrams have much simpler structures after Mellin transform. Correlators in Mellin space are very analogous to the flat-space scattering amplitudes, and they are often called Mellin amplitudes. We will demonstrate the ideas by studying a few non-trivial examples.

### 12.11.2020 (Thursday)

#### Superintegrable systems on moduli spaces of flat connections

Journal Club Nicolai Reshetikhin (Berkeley)

 at: 15:15 Otherroom Zoom, instructions in abstract abstract: Part of London Integrability Journal Club. New participants should register using the form at integrability-london.weebly.com. The link will be emailed.

### 09.11.2020 (Monday)

#### Branes and the moduli space of instantons

Journal Club Amihay Hanany (Imperial College)

 at: 10:30 Otherroom Online abstract: The first recorded lecture of the London Theory Institute for PhD Students. Link to recording and problems (to be solved in live Zoom session next Monday) as well as registration details at https://lonti.weebly.com/ and https://youtu.be/CGDNipeuVEs Instantons, or solutions to the self dual Yang Mills (SDYM) equations are well known solutions, introduced in the mid 70s and played a role in a host of applications in QFT and String Theory. This talk will show a simple brane construction which allows the computation of the moduli space of solutions to the SDYM equations, introduce the student to the world of quivers, and demonstrate simple computations which allow evaluations of these moduli spaces.

### 05.11.2020 (Thursday)

#### Non-planar N=4 SYM: from integrability to quantum chaos

Journal Club Tristan McLoughlin (Trinity College Dublin)

 at: 15:15 Otherroom Zoom, instructions in abstract abstract: In this talk we will consider the spectrum of anomalous dimensions in N=4 super-Yang-Mills and related theories. We will first discuss the emergence of quantum chaos as one goes from infinite to finite N and how the perturbative spectrum is described by GOE random matrix theory. We will then describe how the integrability of the planar-limit can be used to rewrite the computation of the leading 1/N corrections to the one-loop anomalous dimensions in terms of scalar products of off-shell Bethe states or, alternatively, hexagon-like functions.---- Part of London Integrability Journal Club. If you are a new participant, please register filling the form at integrability-london.weebly.com. The link will be emailed.

### 02.11.2020 (Monday)

#### Global symmetry, Euclidean gravity, and the black hole information problem

Journal Club Daniel Harlow (MIT)

 at: 15:00 Otherroom virtual abstract: Part of the London Black Hole Information Paradox Journal Club (for Zoom link, please subscribe here: https://forms.gle/wLYi4A72tEUwuzGK6)

### 29.10.2020 (Thursday)

#### The TTbar deformation and a promising 4D generalisation

Journal Club Roberto Tateo (University of Torino)

 at: 15:15 Otherroom Zoom, instructions in abstract abstract: Two-dimensional field theories deformed by Zamolodchikov's TTbar operator have recently attracted the attention of theoretical physicists due to the many important links with string theory and AdS/CFT. In this talk, I will describe various classical and quantum aspects of this particular irrelevant perturbation, including its geometrical interpretation at the classical level. I will also introduce a generalisation of this geometrical framework to 4D field theories, and discuss some of the interesting differences with the 2D case. ---- Part of London Integrability Journal Club. If you are a new participant, please register filling the form at integrability-london.weebly.com. The link will be emailed.

### 22.10.2020 (Thursday)

#### An exact AdS/CFT correspondence

Journal Club Lorenz Eberhardt (IAS)

 at: 15:15 Otherroom Zoom, instructions in abstract abstract: One incarnation of the AdS/CFT correspondence is the duality between the symmetric product orbifold of T4 and superstrings on AdS3xS3xT4 with one unit of NS-NS flux. Compared to other instances of AdS/CFT, this duality is much simpler and can in principle be fully understood. I will give a broad overview of the inner workings of the duality from a worldsheet CFT point of view, physical lessons and connections to integrability. ---- Part of London Integrability Journal Club. If you are a new participant, please register filling the form at integrability-london.weebly.com. The link will be emailed.

### 15.10.2020 (Thursday)

#### QQ-system construction for so(2r) spin chains

Journal Club Rouven Frassek (ENS Paris)

 at: 15:15 Otherroom Zoom, instructions in abstract abstract: I will review the QQ-system and oscillator construction of Q-operators for su(r+1) spin chains and discuss its generalisation to so(2r) spin chains. ----- Part of London Integrability Journal Club. If you are a new participant, please register filling the form at integrability-london.weebly.com. The link will be emailed.

### 08.10.2020 (Thursday)

#### Integrability for Feynman Integrals

Journal Club Florian Loebbert (Humboldt University of Berlin)

 at: 15:15 Otherroom Zoom, instructions in abstract abstract: In this talk I give an overview of the Yangian symmetry of Feynman integrals. After reviewing the connection between AdS/CFT integrability and the Yangian symmetry of massless Feynman graphs, I discuss the idea to bootstrap Feynman integrals based on the Yangian constraints. Then I show that also in the massive case large classes of Feynman integrals are constrained by a Yangian extension of dual conformal symmetry. When translated to momentum space, this leads to a novel massive generalization of ordinary conformal symmetry. Finally, I argue that these features of massive Feynman integrals can be understood as the integrability of planar scattering amplitudes in a massive version of the so-called fishnet theory, which is obtained as a double-scaling limit of N=4 super Yang-Mills theory on the Coulomb branch. ---- Part of London Integrability Journal Club. If you are a new participant, please register filling the form at integrability-london.weebly.com. The link will be emailed.

### 01.10.2020 (Thursday)

#### Multi-point Bootstrap and Integrability

Journal Club Pedro Vieira (ICTP SAIFR )

 at: 15:00 Otherroom Zoom, instructions in abstract abstract: t.b.a. ------- Part of London Integrability Journal Club. If you are a new particiant, please register using the form on our website integrability-london.weebly.com. The link will be emailed.

### 24.09.2020 (Thursday)

#### Geometrical four-point functions in the 2d critical Q-state Potts model

Journal Club Yifei He (IPhT Saclay)

 at: 15:00 Otherroom Zoom, instructions in abstract abstract: An important example among the 2d geometrical critical phenomena is the critical Q-state Potts model, which describes the percolation in the limit Q-->1. In this talk I will consider the problem of determining the geometrical four-point functions (cluster connectivities) in this model. Connections with the minimal models are made which uncover remarkable properties of the Potts amplitudes. Such properties allow to deduce the existence of "interchiral conformal blocks" which can be constructed using the degeneracy in the Potts spectrum. Using these, I will then determine the four-point functions through numerical bootstrap. In addition, I will also discuss the logarithmic nature of the Potts CFT and hints of a full analytic solution of the model. ----- Part of London Integrability Journal Club. New participants please register using the form at integrability-london.weebly.com. The link will be emailed.

### 17.09.2020 (Thursday)

#### 't Hooft operators and Q-functions

Journal Club Davide Gaiotto (Perimeter Institute)

 at: 15:00 Otherroom Zoom, instructions in abstract abstract: I will describe the role of 't Hooft operators in 4d Chern-Simons theory and applications to integrability. --------------------- Part of London Integrability Journal Club. If you are a new participant, please register using the form at integrability-london.weebly.com. The link will be emailed.

### 23.07.2020 (Thursday)

#### Pre-fundamental representations for the Hubbard model and AdS/CFT

Journal Club Carlo Meneghelli (Oxford)

 at: 15:00 Otherroom Zoom, instructions in abstract abstract: There is a class of representations of quantum groups, referred to as prefundamental representations, that plays an important role in the solution of integrable models. The first example of such representations was given by V. Bazhanov, S. Lukyanov and A. Zamolodchikov in the context of two dimensional conformal field theory in order to construct Baxter Q-operators as transfer matrices. At the same time, there is a rather exceptional quantum group that governs the integrable structure of the one dimensional Hubbard model and plays a fundamental role in the AdS/CFT correspondence. In this talk I will introduce prefundamental representations for this quantum group, explain their basic properties and discuss some of their applications. ------------- Part of London Integrability Journal Club. New participants please register at integrability-london.weebly.com to receive the link. (Registration is needed only once).

### 16.07.2020 (Thursday)

#### Density matrix for the 2D black hole from an integrable spin chain

Journal Club Sergei Lukyanov (Rutgers and Kharkevich IITP)

 at: 15:00 Otherroom Zoom, instructions in abstract abstract: Twenty years ago Maldacena, Ooguri and Son constructed a modular invariant partition function for the Euclidean black hole (cigar) NLSM. They also proposed an expression for the corresponding density matrix. This result played a key role in the formulation of the remarkable conjecture by Ikhlef, Jacobsen and Saleur that the Euclidean black hole NLSM underlies the critical behaviour of a certain integrable spin chain. In this talk we critically reexamine the above proposals. The talk is based on the recent (unpublished) joint work with V. Bazhanov and G. Kotousov. ------------------------ Part of London Integrability Journal Club. New participants please register at integrability-london.weebly.com to receive the link. (Registration is needed only once).

### 15.07.2020 (Wednesday)

#### D0-brane matrix model and holography

Journal Club Masanori Hanada (University of Surrey)

 at: 11:00 Otherroom Virtual abstract: The D0-brane matrix model (the BFSS matrix model and the BMN matrix model) can describe various objects including type IIA black zero-brane, M-theory black hole, M2-branes and M5-branes. We study this theory from several different angles. We put the emphasis on the importance of the dynamics of eigenvalues of matrices, and more generally, color degrees of freedom. Furthermore we explain how the Euclidean theory can be studied by using the Monte Carlo method, and discuss the future directions. If you have a good idea we can test it on computer together! Part of the Black Hole Information Paradox Journal Club. Please email damian.galante@kcl.ac.uk for link to the meeting.

### 09.07.2020 (Thursday)

#### Solving the Yang-Baxter equation

Journal Club Marius de Leeuw (Trinity College Dublin)

 at: 15:00 Otherroom Zoom, instructions in abstract abstract: The Yang-Baxter equation is an important equation that appears in many different areas of physics. It signals the presence of integrable structures which appear in topics ranging from condensed matter physics to holography. In this talk I will discuss a new method to find all regular solutions of the Yang-Baxter equation by using the so-called boost automorphism. The main idea behind this method is to use the Hamiltonian rather than the R-matrix as a starting point. I will demonstrate our method by classifying all solutions of the Yang-Baxter equation of eight-vertex type. I will also consider certain 9x9 and 16x16 solutions and give new integrable models in all of these cases. As a further application, I will discuss all integrable deformations of R-matrices that appear in the lower-dimensional cases of the AdS/CFT correspondence. -------------------------- Part of London Integrability Journal Club. New participants please register at integrability-london.weebly.com for the link. (Registration is only needed once).