Singularities in reductions of Shimura varieties

Thomas Haines
University of Maryland
May 2, 2019

The singularities in the reduction modulo $p$ of the modular
curve $Y_0(p)$ are visualized by the famous picture of two curves
meeting transversally at the supersingular points. It is a fundamental
question to understand the singularities which arise in the reductions
modulo $p$ of integral models of Shimura varieties. For PEL type
Shimura varieties with parahoric level structure at $p$, this question
has been studied since the 1990's. Due to the recent construction of

Globally Consistent Three-family Standard Models in F-theory

Mirjam Cvetic
University of Pennsylvania
April 29, 2019

We present recent advances in constructions of globally consistent 
F-theory compactifications with the exact chiral spectrum of the minimal 
supersymmetric Standard Model. We highlight the first such example and 
then turn to a subsequent systematic exploration of the landscape of 
F-theory three-family Standard Models with a gauge coupling unification. 
Employing algebraic geometry techniques, all global consistency 
conditions of these models can be reduced to a single criterion on the 

Anomalies in the Space of Couplings and Dynamical Applications

Clay Cordova
Member, School of Natural Sciences, IAS
April 26, 2019

Anomalies are invariants under renormalization group flow which lead to powerful constraints on the phases of quantum field theories.  I will explain how these ideas can be generalized to families of theories labelled by coupling constants like the theta angle in gauge theory.  Using these ideas we will be able to prove that certain systems, such as Yang-Mills theory in 4d, necessarily have a phase transition as these parameters are varied.  We will also show how to use the same ideas to constrain the dynamics of defects where coupling constants vary in spacetime.

Chow motives, L-functions, and powers of algebraic Hecke characters

Laure Flapan
Northeastern University/MSRI
April 22, 2019

The Langlands and Fontaine–Mazur conjectures in number theory describe when an automorphic representation f arises geometrically, meaning that there is a smooth projective variety X, or more generally a Chow motive M in the cohomology of X, such that there is an equality of L-functions L(M,s) = L(f,s). We explicitly describe how to produce such a variety X and Chow motive M in the case of powers of certain automorphic representations, called algebraic Hecke characters. This is joint work with J. Lang.