Seminars Sorted by Series

Mathematical Conversations

Feb
19
2025

Mathematical Conversations

Cohomology Theories and Formal Groups
6:00pm|Simons Hall Dilworth Room

In the 1960's, Quillen found a remarkable relationship between a certain class of cohomology theories and the theory of formal groups. This discovery has had a profound impact on algebraic topology. In this talk, I'll give a brief exposition of...

Feb
26
2025

Mathematical Conversations

How and Why to Formalize Mathematics
6:00pm|Simons Hall Dilworth Room

After a short crash course in using Lean to formalize mathematics, we will discuss potential applications to and implications for mathematics education, publication, and research.

Mar
05
2025

Mathematical Conversations

Fair Duels, Digital Halftoning, and Other Mathematical Bit-Balancing Acts
6:00pm|Simons Hall Dilworth Room

What are some of the ways in which binary-valued functions can accurately approximate continuous-valued ones? This talk will be a gentle exposition of the mathematics of "noise-shaping quantization" presented through motivating applications. We will...

Mar
12
2025

Mathematical Conversations

The Mathematical Storytelling of Sand Drawings.
6:00pm|Simons Hall Dilworth Room

Sand drawings appear in many cultures coming, for instance, from South India, Oceania, and Africa.

We will focus on the Chowke people who have a beautiful tradition that combines mathematics and storytelling. In their free time, they would engage in...

Mar
19
2025

Mathematical Conversations

On Stable Commutator Length and its New Relatives
6:00pm|Simons Hall Dilworth Room

Stable commutator length (or scl) of group elements is a well-known, simple-to-define invariant, related to bounded cohomology and quasimorphisms. Yet its simple definition is a trap: many of the exciting developments around scl required "better"...

Mar
26
2025

Mathematical Conversations

Mind Your q’s — Quantum Rules on the Grassmannian
6:00pm|Simons Hall Dilworth Room

The theory of quantum cohomology was developed in the early 1990s by physicists working in the field of superstring theory.

Mathematicians then discovered applications to enumerative geometry, counting the number of rational curves of a given degree...

Apr
02
2025

Mathematical Conversations

Expansion and Robustness
6:00pm|Simons Hall Dilworth Room

Expansion is an important notion in graphs, and comes in several equivalent formulations, including (1) convergence of random walks, (2) having no small cuts, and (3) having a large spectral gap. I will talk about a higher dimensional generalization...

Apr
09
2025

Mathematical Conversations

Aperiodic Square Tilings and Lattices in Products of Trees
6:00pm|Simons Hall Dilworth Room

We will consider finite collections of squares tiles, and ask when we can tile the whole plane in an interesting way. This question is related to the algebraic structure of ‘lattices in products of trees’, which are discrete groups acting...

Apr
16
2025

Mathematical Conversations

Visual Aspects of Gaussian Periods
6:00pm|Simons Hall Dilworth Room

Gaussian periods are certain sums of roots of unity.  Gauss introduced them in his work on straight edge and compass constructions of regular polygons.  Since then, Gaussian periods have played important roles in number theory and beyond.  It turns...

Oct
08
2025

Mathematical Conversations

Open Books and Secret Agents
6:00pm|Birch Garden, Simons Hall

An open book is a topological concept aptly named by Elmar Winkelnkemper.

The binding of the book is a fibred knot (of any dimension), and open books and fibred knots are essentially synonymous. Currently the standard reference for the existence and...

Oct
22
2025

Mathematical Conversations

The Chromatic Picture of Stable Homotopy Theory
6:00pm|Birch Garden, Simons Hall

There is a deep connection between stable homotopy theory and the theory of formal groups, first noticed by Quillen. I will describe this connection, and explain how this has led to the chromatic picture of the stable homotopy category.

Nov
05
2025

Mathematical Conversations

Three Fingers are Enough to Count to N (Or, How Not to Hang a Painting)
6:00pm|Simons Hall Dilworth Room

In this talk, I’ll describe one of the most surprising algorithms in computer science: a way to count arbitrarily high while maintaining just three bits of state and a clock. It turns out that the main idea behind the algorithm also appears in a...

Nov
12
2025

Mathematical Conversations

Speaking of Values ...
6:00pm|Simons Hall Dilworth Room

I will talk very briefly about what number theorists call special values of $zeta$ and L-functions. I will start with some familiar, classical equalities and will attempt to touch upon some less familiar (mostly conjectural and very far reaching)...

Dec
03
2025

Mathematical Conversations

Mathematics of the Heart and Spirit: Some Thoughts on Grothendieck
6:00pm|Rubenstein Commons | Meeting Room 5

Alexander Grothendieck was one of the greatest thinkers, and one of the most unusual personalities, in the history of science.  In addition to some biographical details, this talk will offer a perspective on his approach to mathematics.

Dec
10
2025

Mathematical Conversations

Ghosts in My House
6:00pm|Simons Hall Dilworth Room

I will start with an interesting symmetry of plane quadrilaterals and see what mathematics we can reach within 20 minutes.   Also I will explain the title.

Feb
04
2026

Mathematical Conversations

That's a Big Hypercube
Jordan Ellenberg
6:00pm|Simons Hall Dilworth Room

In a recent collaboration with a group of algebraic combinatorists at ICERM, we came across a rather surprising set of permutations, which (in a natural sense I'll explain in the talk) form an unexpectedly gigantic hypercube.  This set of...

Feb
11
2026

Mathematical Conversations

Lost in a Rough Flow
6:00pm|Simons Hall Dilworth Room

A Lipschitz velocity field gives a reassuring picture of particle motion: each starting point traces a single, well-defined trajectory. But many velocity fields arising in geometry, kinetic theory, and fluid dynamics are far rougher, and then the...

Feb
18
2026

Mathematical Conversations

Does Life Compute?
6:00pm|Simons Hall Dilworth Room

I'll discuss our attempts to model problems of bio molecular assembly using simple geometric constructions. We contrast how nature makes polyhedra with classical constructions. The issue that really bothers me is this: biomolecular codes are...

Feb
25
2026

Mathematical Conversations

Symmetry and Regularity in Geometry
6:00pm|Simons Hall Dilworth Room

We will give a hopefully light hearted introduction to the behavior of some geometrically motivated equations, mostly in the context of examples and broad discussion of Einstein manifolds (though our story has counterparts in many areas). A theme...

Mathematical Physics Seminar

Nov
04
2004

Mathematical Physics Seminar

Conformal Invariance and the Diffusion on Moduli Space for Radial SLE
4:00pm|S-101

We show that a random simple curve in a planar n-connected domain that is conformally invariant and satisfies a Markovian-type property, can be described by a diffusion on a moduli space of dimension 3n-2. Under a natural symmetry condition...

Nov
09
2004

Mathematical Physics Seminar

Matrix Models, Random Partitions, Planar Graphs and Random Surfaces
4:00pm|S-101

"We give an overview of the ideas and techniques relating these seemingly different subjects. I will start from the classical examples, such as enumeration of triangulations by means of one matrix model and counting of colored graphs (Ising model on...

Nov
16
2004

Mathematical Physics Seminar

Seiberg-Witten Theory and Random Partitions
4:00pm|S-101

This will be an overview of the paper hep-th/0306238 written jointly with N. Nekrasov. Our main idea is the interpretation of the low-energy effective prepotential of the N=2 supersymmetric gauge theory as the free energy of a certain natural...

Dec
07
2004

Mathematical Physics Seminar

Large Deviations for a Point Process of Bounded Variability
Eugene Speer
4:00pm|S-101

A (one-dimensional) translation invariant point process of bounded variability is one in which the variance of the number of particles in any interval is bounded, uniformly in the length of the interval. This represents a strong suppression of...

Dec
14
2004

Mathematical Physics Seminar

Jamming and k-core Percolation
Andrea Liu
4:00pm|S-101

We have proposed that the glass transition is one example of a broader class of jamming transitions, where systems can develop extremely long stress relaxation times in disordered states as temperature is lowered, an applied shear stress is lowered...

Jan
23
2006

Mathematical Physics Seminar

Loop-Erased Random Walk
2:00pm|S-101

We will discuss this model of a random simple path and its connection to spanning trees, matrix formulas, the Potts model and SLE. Time permitting, we shall discuss the proof the it has a scaling limit in three dimensions. No prior knowledge will be...

Jan
30
2006

Mathematical Physics Seminar

Matrix Models for Random Circular Ensembles
2:00pm|S-101

We construct an ensemble of (sparse) random matrices whose eigenvalues follow the Gibbs distribution for n particles of Coulomb gas on the unit circle at any given inverse temperature. Our approach combines elements from the theory of orthogonal...

Feb
01
2006

Mathematical Physics Seminar

Universality for Orthogonal and Symplectic Ensembles
Percy Deift
2:00pm|S-101

This is joint work with Dimitri Gioev. The speaker will show how to prove universality in the bulk and at the edge for orthogonal and symplectic ensembles of random matrices with weights of the form exp(-V(x))dx. The method follows the formalism of...

Feb
13
2006

Mathematical Physics Seminar

Lowest Energy States in Non-Relativistic QED
2:00pm|S-101

Within non-relativistic quantum electrodnamics, atoms interacting with the radiation field are expected to have a ground state. It is further expected that the ground state exists independently of the size of the coupling constant $\alpha$ and the...

Feb
20
2006

Mathematical Physics Seminar

Edge and Bulk Currents in 2D Disordered Magnetic Systems
2:00pm|S-101

The integer quantum Hall effect (IQHE) entails a very precise quantization of the Hall conductance in a 2D sample at very low temperatures. Depending on whether the currents in the sample are ascribed to the bulk or the edge, two apparently...

Mar
06
2006

Mathematical Physics Seminar

The Thermodynamics Pressure of a Dilute Fermi Gas
Robert Seiringer
2:00pm|S-101

We consider a gas of fermions with non-zero spin at positive temperature $T$. We show that if the range of the interparticle interaction is small compared to the mean particle distance, the thermodynamic pressure differs to leading order from the...

Apr
10
2006

Mathematical Physics Seminar

On the Fourier Law for Coupled Oscillators
Anti Kupiainen
2:00pm|S-101

We discuss the problem of deriving Fourier's law of heat transport in a Hamiltonian system of coupled anharmonic oscillators subject to boundary noise and derive it in a closure approximation of the stationary state of the system.

Apr
14
2006

Mathematical Physics Seminar

Blow Ups in Complex Solutions of the 3D-Navier-Stokes System and Renormalization Group Method
Yakov Sinai
4:00pm|S-101
Apr
24
2006

Mathematical Physics Seminar

Droplet Minimizers for Free Energy Functionals with a Liquid-Vapor Transition at the Droplet Formation Threshold
Eric Carlen
2:00pm|S-101

We examine several non convex free energy functionals involving a double well potential, and an energy term that penalizes variation in the mass density field. The simplest example is the so--called Cahn--Hilliard functional, which is purely...

May
03
2006

Mathematical Physics Seminar

Directed Polymers with Quenched Randomness: Delocalization Transition and Critical Properties
Fabio Toninelli
2:00pm|S-101

I will present results on the critical behavior of directed polymer models interacting with a defect line, in presence of quenched disorder. These models show a localization-delocalization phase transition. Our main result is that the transition in...

Sep
18
2006

Mathematical Physics Seminar

Cardy's Formula for Certain Models of the Bond-Triangular Type
Lincoln Chayes
4:00pm|S-101

A model based on independent bond percolation is defined. It is demonstrated that this model exhibits critical behavior and, at least at the level of Cardy's formula, has the same limiting continuum behavior as the site model.

Nov
01
2006

Mathematical Physics Seminar

Critical 2d Models on the Annulus
John Cardy
2:30pm|S-101

I conjecture a form for the scaling limit of the partition function of the critical O(n) and Potts models on the annulus, using Coulomb gas methods. This has several subtleties whose elucidation sheds light on the nature of the Coulomb gas mapping.

Nov
10
2006

Mathematical Physics Seminar

Random Band Matrices
4:00pm|S-101

Random band matrices have been proposed as an effective, or toy, model for a disorder induced localization-delocalization transition of eigenstates. Most results about these matrices, and the transition, are based on numerics or on calculations with...