13:00
Bootstrapping the 3d Ising Stress Tensor
Abstract
I will discuss the recent progress in the numerical bootstrap of the 3d Ising CFT using the correlation functions of stress-energy tensor and the relevant scalars. This numerical bootstrap setup gives excellent results which are two orders of magnitude more accurate than the previous world's best. However, it also presents many significant technical challenges. Therefore, in addition to describing in detail the numerical results of this work, I will also explain the state-of-the art numerical bootstrap methods that made this study possible. Based on arXiv:2411.15300 and work in progress.
14:00
SPECIAL STRING THEORY SEMINAR: An infrared on-shell action in asymptotically flat spacetimes
Abstract
One of the main entries in the AdS/CFT dictionary is a relation between the bulk on-shell partition function with specified boundary conditions and the generating function of correlation functions of primary operators in the boundary CFT. In this talk, I will show how to construct a similar relation for gravity in 4d asymptotically flat spacetimes. For simplicity, we will restrict to the leading infrared sector, where a careful treatment of soft modes and their canonical partners leads to a non-vanishing on-shell action. I will show that this action localizes to a codimension-2 surface and coincides with the generating function of 2d CFT correlators involving insertions of Kac-Moody currents. The latter were previously shown, using effective field theory methods, to reproduce the leading soft graviton theorems in 4d. I will conclude with comments on the implications of these results for the computation of soft charge fluctuations in the vacuum.
16:00
Parametrising abelian surfaces with RM by Z[√2] using Richelot isogenies
Abstract
Correlations of almost primes
Abstract
The Hardy-Littlewood generalised twin prime conjecture states an asymptotic formula for the number of primes $p\le X$ such that $p+h$ is prime for any non-zero even integer $h$. While this conjecture remains wide open, Matom\"{a}ki, Radziwi{\l}{\l} and Tao proved that it holds on average over $h$, improving on a previous result of Mikawa. In this talk we will discuss an almost prime analogue of the Hardy-Littlewood conjecture for which we can go beyond what is known for primes. We will describe some recent work in which we prove an asymptotic formula for the number of almost primes $n=p_1p_2 \le X$ such that $n+h$ has exactly two prime factors which holds for a very short average over $h$.
16:00
Symmetric power functoriality for modular forms
Abstract
Some of the simplest expected cases of Langlands functoriality are the symmetric power liftings Sym^r from automorphic representations of GL(2) to automorphic representations of GL(r+1). I will discuss some joint work with Jack Thorne on the symmetric power lifting for holomorphic modular forms.
12:45
Twisted BRST quantization and localization in supergravity
Abstract
Supersymmetric localization is a powerful technique to evaluate a class of functional integrals in supersymmetric field theories. It reduces the functional integral over field space to ordinary integrals over the space of solutions of the off-shell BPS equations. The application of this technique to supergravity suffers from some problems, both conceptual and practical. I will discuss one of the main conceptual problems, namely how to construct the fermionic symmetry with which to localize. I will show how a deformation of the BRST technique allows us to do this. As an application I will then sketch a computation of the one-loop determinant of the super-graviton that enters the localization formula for BPS black hole entropy.
14:15
The geometry of constant mean curvature disks embedded in R^3.
Abstract
In this talk I will discuss results on the geometry of constant mean curvature (H\neq 0) disks embedded in R^3. Among other
things I will prove radius and curvature estimates for such disks. It then follows from the radius estimate that the only complete, simply connected surface embedded in R^3 with constant mean curvature is the round sphere. This is joint work with Bill Meeks.
14:00
Floer cohomology and Platonic solids
Abstract
We consider Fano threefolds on which SL(2,C) acts with a dense
open orbit. This is a finite list of threefolds whose classification
follows from the classical work of Mukai-Umemura and Nakano. Inside
these threefolds, there sits a Lagrangian space form given as an orbit
of SU(2). We prove this Lagrangian is non-displaceable by Hamiltonian
isotopies via computing its Floer cohomology over a field of non-zero
characteristic. The computation depends on certain counts of holomorphic
disks with boundary on the Lagrangian, which we explicitly identify.
This is joint work in progress with Jonny Evans.