Triangle Seminars

Abstract:
We investigate emergent gravity extending the paradigm of the AdS/CFT correspondence. The emergent graviton is associated to the (dynamical) expectation value of the energy-momentum tensor. We derive the general effective description of such dynamics, and apply it to the case where a hidden theory generates gravity that is coupled to the Standard Model. In the linearized description, generically, such gravity is massive with the presence of an extra scalar degree of freedom. The propagators of both the spin-two and spin-zero modes are positive and well defined. The associated emergent gravitational theory is a bi-gravity theory, as is (secretly) the case in holography. The background metric on which the QFTs are defined, plays the role of dark energy and the emergent theory has always as a solution the original background metric. In the case where the hidden theory is holographic, the overall description yields a higher-dimensional bulk theory coupled to a brane. The effective graviton on the brane has four-dimensional characteristics both in the UV and IR and is always massive.

[please email a.held@imperial.ac.uk for zoom link or password]

Abstract:
I will explain a method of constructing BPS algebras for string theory on generic toric Calabi-Yau threefolds. The approach is a ``bootstrap” method based on the 3D colored crystals that describe BPS states of the system. The resulting algebras are quiver Yangians Y(Q,W) that are associated with the quiver and the superpotential of the theory. [Please email alejandro.cabo_bizet@kcl.ac.uk for zoom link]

Abstract:
Conformal partial wave expansion provide Fourier-like decompositions of correlation functions in Conformal Field Theory. Despite their fundamental importance, conformal
partial waves remain poorly understood, at least beyond the case of four local fields.
In the last few years, a deep relation with integrable quantum mechanical models has emerged. It offers a wealth of powerful new algebraic methods to study and construct conformal partial waves e.g. for general supermultiplets, non-local (line-, surface-) operators and multi-point correlation functions. In my talk I will use ideas from harmonic analysis of the conformal group to embed conformal partial waves into the
framework of Gaudin integrable models and then discuss several concrete ramifications as trigonometric and elliptic Calogero-Sutherland models. The latter are relevant for multi-point blocks of scalar fields. ––- Part of London Integrability Journal Club. Please register at integrability-london.weebly.com/registration.html if you are a new participant.

Abstract:
We propose an operator product expansion for planar form factors of local operators in N = 4 SYM theory. This expansion is based on the dual conformal symmetry of these objects or, equivalently, the conformal symmetry of their dual description in terms of periodic Wilson loops. A form factor is decomposed into a sequence of known pentagon transitions and a new universal object that we call the “form factor transition”. This transition is subject to a set of non-trivial bootstrap constraints, which allows us to bootstrap it at any value of the coupling. We evaluate the form factor transition for MHV form factors of the chiral half of the stress tensor supermultiplet at leading order in perturbation theory and use it to produce OPE predictions at any loop order. We match the one-loop and two-loop predictions with data available in the literature. [for zoom link contact jung-wook(dot)kim(at)qmul(dot)ac(dot)uk]