We briefly overview how historically string theory led theoretical physics first to algebraic/differential geometry, and then to computational geometry, and now to data science. Using the Calabi-Yau landscape - accumulated by the collaboration of physicists, mathematicians and computer scientists over the last 4 decades - as a starting-point and concrete playground, we then launch to review our recent programme in machine-learning mathematical structures and address the tantalizing question of how AI helps doing mathematics, ranging from geometry, to representation theory, to combinatorics, to number theory. Zoom Link: https://us02web.zoom.us/j/83496714171?pwd=bld3QmQ2c21laWxEWTd6ejVQbjZ5dz09 (contact dionysios.anninos@kcl.ac.uk for password)

Gravity is a fundamental theory of physics, but so weak, that we still know very little about it. A new exciting development is that the Laser Interferometer Gravitational-Wave Observatory (LIGO) can now measure the effects when massive black holes collide in the Universe. This has stimulated many new and interesting studies of gravitational interactions. I will in this talk discuss recent computational advances and discuss how to derive results for observables in general relativity from amplitudes.

Modified gravity models have been developed to try to explain the observed acceleration of the expansion of the Universe. Such models introduce and extra, fifth force, and usually employ a screening mechanism whereby the fifth force is screened in the solar system but unscreened cosmologically. Recent developments in laboratory experiments mean that such theories can now be tested and constrained using existing experiments. In particular innovative Casimir force experiments can be used to constrain such theories. This enables Einstein gravity to be tested on scales not previously explored. ----- Follow the usual link or contact the organisers (Antoine Bourget and Edoardo Vescovi). Student introduction at 13:00.

TBA

Inflation, an era of accelerated expansion of the universe prior to the radiation phase, constitutes the paradigm of primordial cosmology. Within this paradigm, the simplest single-field slow-roll models economically explain all current data. However, the sensitivity of inflation to Planck scale physics, and the fact that ultraviolet completions of inflation invariably involve extra fields coupled to the inflaton, indicate that these models constitute at best a phenomenological description that emerges from a more realistic physical framework. In this talk, I will describe recent works that aim at understanding the consequences of the presence of several degrees of freedom during inflation. In particular, I will highlight that realistic models are characterized not only by their potentials but also by the internal geometries in which the fields live in, and I will discuss related novel phenomena that have been studied in the past years. ----- Contact the organisers (Antoine Bourget and Edoardo Vescovi) for the link.

I will give an introduction to the Quantum Spectral Curve in AdS/CFT. This is an integrability-based framework which provides the exact spectrum of planar N = 4 super Yang-Mills theory (and of the dual string model) in terms of a solution of a Riemann-Hilbert problem for a finite set of functions. I review the underlying QQ-relations starting from simple spin chain examples, and describe the special features arising for AdS/CFT. I will also present some pedagogical examples to show the framework in action. Lastly I will briefly discuss its recent applications for correlation functions. Based on the review arXiv:1911.13065. NOTE: online seminar using Zoom. Please register to the mailing list on integrability-london.weebly.com to participate.

I will discuss the recent paper 2003.02770 with the title above (by J. Nian and L. Pando Zayas). Link to meeting: here

The Quantum Spectral Curve (QSC) is a powerful integrability-based framework capturing the exact spectrum of planar N=4 SYM. We present first evidence that it should also play an important role for computing exact correlation functions. We compute the correlator of 3 scalar local operators connected by Wilson lines forming a triangle in the ladders limit, and show that it massively simplifies when written in terms of the QSC. The final all-loop result takes a very compact form, suggesting its interpretation via Sklyanin's separation of variables (SoV). We discuss work in progress on extending these results to local operators. We also derive, for the first time, the SoV scalar product measure for gl(N) compact and noncompact spin chains. Based on arXiv:1910.13442, 1907.03788, 1802.0423.

I will discuss recent developments in constructions of 5d N=1 supersymmetric gauge theories and their UV fixed points, which are strongly-coupled SCFTs. The lectures will start with some background on 5d gauge theories, their Coulomb branch and effective action, as well as their constructions in M-theory on non-compact Calabi-Yau threefolds. In the second lecture I will discuss some new developments of various groups in the past year.

In this talk, based on the work to appear, we present an alternative representation of the conformal block with external scalars in general spacetime dimensions in terms of a finite summation over Appell fourth hypergeometric function, and its generalization to the primary operator exchange with continuous spin which is relevant for Lorentzian spacetime. Using these results we apply the Lorentzian inversion formula to compute so-called crossing kernel in general spacetime dimensions, and the result can be written as a double infinite summation over certain Kempe de Feriet hypergeometric functions. During the talk, we will introduce various physical quantities and discuss their subtitles and applications.

We test various conjectures on quantum gravity with general 6d string compactifications in the framework of F-theory. Starting with a gauge theory coupled to gravity, we first analyze the limit in Kähler moduli space where the gauge coupling tends to zero while gravity is kept dynamical. A key observation is made about the appearance of a tensionless string in such a limit. For a more quantitative analysis, we focus on a U(1) gauge symmetry and determine the elliptic genus of this string in terms of certain meromorphic weak Jacobi forms, of which modular properties allow us to determine the charge-to-mass ratios of certain string excitations. A tower of these asymptotically massless charged states are then confirmed to satisfy the (sub-)Lattice Weak Gravity Conjecture, the Completeness Conjecture, and the Swampland Distance Conjecture. We interpret their charge-to-mass ratios in two a priori independent perspectives. All of this is then generalized to theories with multiple U(1)s. If time permits, we will also briefly report on our more recent 4-dimensional story.

Disconnected gauge groups have been, at least comparatively, very poorly studied. Yet they may hide very interesting Physics. Recently, a class of gauge theories based on a particular type of disconnected gauge groups, namely principal extensions, has been introduced. Interestingly, such theories naturally implement the gauging of charge conjugation. In this talk, we will describe such construction and study aspects of its Physics. A particularly spectacular by-product of the construction is that these theories have non-freely generated Coulomb branches, thus providing the first counterexample of the long standing standard lore that Coulomb branch are all freely generated.

String theory predicts its own gravity rather than GR. In General Relativity the metric is the only geometric and gravitational field, whereas in string theory the closed-string massless sector comprises a skew-symmetric B-field and the string dilaton in addition to the metric. Furthermore, these three fields transform into each other under T-duality. This hints at a natural augmentation of GR: upon treating the whole closed string massless sector as stringy graviton fields, Double Field Theory may evolve into `Stringy Gravity'. Equipped with an O(D,D) covariant differential geometry beyond Riemann, we spell out the definitions of the stringy Einstein curvature tensor and the stringy Energy-Momentum tensor. Equating them, all the equations of motion of the closed string massless sector are unified into a single expression which we dub the Einstein Double Field Equations.

The topological string is a simplified version of physical string theory. It is of interest because it computes the BPS spectrum of relevant string theory compactifications, but also because it shares structural properties of physical string theory, Dualities and symmetries which often must be argued for arduously in the physical string can often be verified by computation in the topological setting. The central observable of the theory is the topological string partition function Z_top. This quantity has an eerie habit of making surprise appearances in many areas of mathematical physics. Numerous techniques exist for its computation in various expansions in parameters of the theory, yet to date, no satisfactory closed form for this quantity is known. In this talk, after reviewing notions of topological string theory with an emphasis on the interplay between worldsheet and target space physics (one of the structural similarities between the physical and the topological string alluded to above), I will report on progress in computing Z_top in settings where it is related to enigmatic 6d theories.

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).

In this talk, I will discuss about the holography of boundary Conformal Field theory. I will show how boundary Weyl Anomaly can be obtained from holography. New universal relations between the shape dependence of Casimir effects and boundary Weyl anomaly will also be pointed out and discussed from the point of view of holography.

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.

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

In this talk, I will discuss Type IIA brane configurations consisting of D4-branes suspended between NS5-branes which represent a large class of 2d (0,2) quiver gauge theories. We call these new constructions Brane Brick models. These are T-dual to D1-branes over singular toric Calabi-Yau 4-folds and encode information about the probed Calabi-Yau geometry as well as the corresponding GLSM. If time permits, I will present how Brane Brick models naturally realise in terms of a brane configuration 2d (0,2) Gadde-Gukov-Putrov triality.