Triangle Seminars
Wednesday, 7 May 2025
Where is tree-level string theory?
📍 London
Leonardo Rastelli
(Stony Brook U.)
Abstract:
Tree-level string theory extends Einstein gravity by an infinite set of massive higher spin particles. From a purely spacetime perspective (if we didn't know about the worldsheet picture) the consistency of string amplitudes would appear truly miraculous. This prompts the question: is string theory the unique framework for a higher spin extension of gravity? We investigate this question by bootstrap methods, focussing on maximal 10D supergravity. We parametrize theory space by the first few EFT coefficients and by the on-shell coupling of the lightest massive state, and impose on these data causality and positivity constraints. While Type II string theory lives strictly inside the allowed region, we uncover a novel extremal solution of the bootstrap problem, which appears to contain a single linear Regge trajectory. We repeat a similar analysis for supergluon scattering.
Tree-level string theory extends Einstein gravity by an infinite set of massive higher spin particles. From a purely spacetime perspective (if we didn't know about the worldsheet picture) the consistency of string amplitudes would appear truly miraculous. This prompts the question: is string theory the unique framework for a higher spin extension of gravity? We investigate this question by bootstrap methods, focussing on maximal 10D supergravity. We parametrize theory space by the first few EFT coefficients and by the on-shell coupling of the lightest massive state, and impose on these data causality and positivity constraints. While Type II string theory lives strictly inside the allowed region, we uncover a novel extremal solution of the bootstrap problem, which appears to contain a single linear Regge trajectory. We repeat a similar analysis for supergluon scattering.
Posted by: andrea
Thursday, 8 May 2025
Interpolating indices in superconformal N=2 gauge theories in four dimensions
📍 London
Itamar Yaakov
(University of Southampton)
Abstract:
I will discuss work in preparation which relates two quantities in 4d N=2 supersymmetric theories: the superconformal index, which contains information about protected local operators, and the twisted index. I will show that under appropriate restrictions on the theory and the space of supersymmetric deformations, these quantities coincide. I will then discuss some implications for the physics of the theory and its holographic dual.
I will discuss work in preparation which relates two quantities in 4d N=2 supersymmetric theories: the superconformal index, which contains information about protected local operators, and the twisted index. I will show that under appropriate restrictions on the theory and the space of supersymmetric deformations, these quantities coincide. I will then discuss some implications for the physics of the theory and its holographic dual.
Posted by: QMW
Friday, 9 May 2025
A Universal Connection Between 3d N=4 SCFTs and 3d TQFTs
Matthew Buican
(Queen Mary University of London)
Abstract:
I will describe work on a universal relevant deformation that takes local unitary 3d N=4 superconformal field theories to topological quantum field theories. For example, I will describe how Abelian mirror symmetry is related to generalizations of level rank duality, and I will also discuss some more general statements and constraints that arise via t Hooft anomaly matching.
I will describe work on a universal relevant deformation that takes local unitary 3d N=4 superconformal field theories to topological quantum field theories. For example, I will describe how Abelian mirror symmetry is related to generalizations of level rank duality, and I will also discuss some more general statements and constraints that arise via t Hooft anomaly matching.
Posted by: oxford