Week 01.05.2023 – 07.05.2023

In this talk, we start by introducing massive spin-2 theories and reviewing some of their key features. Then, using massive spinor helicity variables, we review an on-shell superspace formalism for massive particles in four dimensions. Finally, we apply this formalism to massive spin-2 amplitudes, deriving all spin-2 cubic vertices that are compatible with supersymmetry and exploring the constraints that adding more supersymmetry has on these vertices. Additionally, we discuss how the massive graviton supermultiplets and cubic superamplitudes can be constructed via a double copy of massive Yang—Mills supermultiplets and cubic superamplitudes. We conclude by commenting on possible future directions such as computing the 4-point massive supersymmetric spin-2 amplitudes and the issues that can arise in a massive double copy for higher point amplitudes.

These three lectures will aim to provide a pedagogical introduction to the dynamics of N=2 supersymmetric gauge theory and the work of Seiberg and Witten. We will assume only basic knowledge of supersymmetry.

Conformal field theories in (1+1)D are key actors in many dramas in physics and mathematics. Their classification has therefore been an important and long-standing problem. In this talk, I will describe the main ideas behind the classification of (most) "small" bosonic CFTs - theories with low central charge (less than 24) and few primary operators (less than 5). I will then highlight two applications of this result. First, I will describe how it can be used in tandem with bosonization and fermionization techniques to establish the classification of chiral fermionic CFTs with central charge less than 23. Second, I will showcase how it can be used to bootstrap the generalized global symmetries of chiral bosonic CFTs. Talk based on arXiv:2208.05486 [hep-th] (joint work with Sunil Mukhi) and arXiv:2303.16921 [hep-th].

The Thirring Model is a covariant quantum field theory of interacting fermions, sharing many features in common with effective theories of two-dimensional electronic systems with linear dispersion such as graphene. For a small number of flavors and sufficiently strong interactions the ground state may be disrupted by condensation of particle-hole pairs leading to a quantum critical point. With no small dimensionless parameters in play in this regime the Thirring model is plausibly the simplest theory of fermions requiring a numerical solution. I will review what is currently known focussing on recent simulations employing Domain Wall Fermions (a formulation drawn from state-of-the-art QCD simulation), to faithfully capture the underlying symmetries at the critical point, focussing on the symmetry-breaking transition, the critical flavor number, and the anomalous scaling of the propagating fermion.

In this talk I will discuss N=(2,2) susy generalisation of Hull's doubled sigma model. The doubled formulation of the worldsheet provides a description of string theory in which T-duality is promoted to a manifest symmetry. Formulation via N=(2,2) superspace provides a doubled formulation for bi-Hermitian/generalised Kahler target spaces. The theory is described by a single function, a doubled-generalised Kahler potential, supplemented with a manifestly N=(2,2) constraint. If time permits I will ilustrate some of the concepts developed on examples.

I will show that self-dual gravity in Euclidean four-dimensional Anti-de Sitter space (AdS4 ) can be described by a minimally coupled scalar field with a cubic interaction written in terms of a deformed Poisson bracket, providing a remarkably simple generalisation of the Plebanski action for self-dual gravity in flat space. This implies a novel symmetry algebra in self-dual gravity, notably an AdS4 version of the so-called kinematic algebra. This provides a concrete starting point for defining the double copy for Einstein gravity in AdS4 by expanding around the self-dual sector. Moreover, I will show that the new kinematic Lie algebra can be lifted to a deformed version of the w1+∞ algebra, which plays a prominent role in celestial holography.

The interpretation of LHC data, and the assessment of possible hints for new physics in the experimental signals, require the precise knowledge of the proton subnuclear structure in terms of its elementary constituents, quarks and gluons. In this talk I will present the fascinating precision frontier that phenomenologists are facing an will describe the challenges behind the determination of proton structure, involving precise perturbative QCD calculations and machine learning techniques. I will show how global fits of the proton might inadvertently ‘fit away’ signals of new physics in the high-energy tails of the distributions that are experimentally measured. A new physics scenario in which the fit of the proton’s structure may completely absorb such signs of new physics is showcased. Strategies to single out such effects and disentangle the inconsistencies that stem from new physics signals are discussed.