Seminars Sorted by Series

Mathematical Conversations

Oct
23
2024

Mathematical Conversations

Dynamics, Computation, and Real Circuit Theory
6:00pm|Birch Garden, Simons Hall

Some people think that the brain is something like a (conscious) computer. But if a brain can compute, why can't a rock, or a river stream? This basic question has been considered by philosophers, physicists, and mathematicians.

It is not entirely...

Oct
30
2024

Mathematical Conversations

The Alexandrov-Fenchel Inequality
6:00pm|Birch Garden, Simons Hall

The Alexandrov-Fenchel inequality---the fundamental log-concavity phenomenon in convex geometry---arose from Minkowski's work in number theory in the late 1800s. It has resurfaced in surprising ways throughout the 20th and 21st centuries in the...

Nov
06
2024

Mathematical Conversations

Not All Lakes are Circular: When Recreational Math Meets Analysis
6:00pm|Birch Garden, Simons Hall

You are swimming at the center of a circular lake with a bear waiting on the shore. The bear, unable to swim, moves four times faster on land than you do in water, but once on land, you can outrun it. Can you escape?

This classic riddle has been...

Nov
13
2024

Mathematical Conversations

Characterizations of Einstein Manifolds through Analysis on Path Space
6:00pm|Birch Garden, Simons Hall

The Ricci curvature of a Riemannian manifold is best viewed as the right replacement for the (nonlinear) laplacian of the metric g, which in particular explains why it so often appears in geometry and analysis.  Most commonly one studies either...

Dec
04
2024

Mathematical Conversations

Entropy, Coding and Mean Dimension
6:00pm|Birch Garden, Simons Hall

How much information is needed to describe a trajectory in a dynamical system? The answer depends on what one means by dynamical system.

If our system is a probability measure space, and one has a time evolution (with either discrete or continuous...

Dec
11
2024

Mathematical Conversations

Adding integers; when your fingers run out
6:00pm|Simons Hall Dilworth Room

In primary school, I never got beyond adding integers and the questions have only been piling up since! What do sets of integers $A$ look like if they generate only a few sums with the elements of another set $B$? Meester Jaap (my primary teacher)...

Feb
05
2025

Mathematical Conversations

The Unfinished Story of the Mahler Conjecture.
6:00pm|Simons Hall Dilworth Room

The polar body is a fundamental concept in functional and convex analysis, representing a special convex set associated with any convex subset of Euclidean space. One can think of the polar operation as, roughly speaking, the "inverse" of convex...

Feb
12
2025

Mathematical Conversations

Homology Classes of Algebraic Surfaces in 4-Spaces
6:00pm|Simons Hall Dilworth Room

I will explore two questions about projections of geometric objects in 4-dimensional spaces:

(1) Let $A$ be a convex body in $\mathbb{R}^4$, and let $(p_{12}, p_{13}, p_{14}, p_{23}, p_{24}, p_{34})$ be the areas of the six coordinate projections of...

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...

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...

Dec
06
2006

Mathematical Physics Seminar

The Renormalisation Group II
2:30pm|S-101

This is continuation of the previous seminar in which the formulation of the renormalisation group is given in more detail: a space of statistical mechanical models is defined. The renormalisation group is a map on this space and there is a basic...

Feb
07
2007

Mathematical Physics Seminar

Random Conformal Snowflakes
2:30pm|S-101

In this talk we introduce a new class of random fractals which we call conformal snowflakes. We study fine structure of harmonic measure on theses snowflakes. It turns out that in this case the multifractal spectrum of harmonic measure is related to...

Feb
16
2007

Mathematical Physics Seminar

Optimal Transport and Geometric Inequalities
1:30pm|S-101

Since the end of the nineties, the relations of optimal transport with many functional inequalities with geometric content has been revealed and explored by several authors (Barthe, Caffarelli, Cordero, McCann, Otto and others). Sobolev inequalities...

Feb
21
2007

Mathematical Physics Seminar

Full Regularity for the Dissipative Quasi-Geostrophic Equations
2:00pm|S-101

We will present some recent developments in the quasi-geostrophic equations. We show that local solutions to critical and super-critical dissipative quasi-geostrophic equations have higher regularity, although one gets lower derivative in the...

Mar
07
2007

Mathematical Physics Seminar

The Geometry of Grains
4:00pm|S-101

A metal or ceramic is naturally decomposed into cells called "grains". The geometry of this cell complex influences the properties of the material. Some interesting mathematical problems arise in trying to understand the time evolution of these...

Jan
28
2009

Mathematical Physics Seminar

Large Deviations of the Current in Non-Equilibrium Systems
Thierry Bodineau
11:15am|S-101

Using the hydrodynamic limit theory, we will review the large deviations of the heat current through a diffusive system maintained off equilibrium by two heat baths at unequal temperatures. We will also discuss a toy model for dissipative dynamics...

Feb
04
2009

Mathematical Physics Seminar

A Statistical Mechanics Model of Random Matrices
Tom Spencer
11:15am|S-101

Spectral prosperities of random matrices can be described in terms of correlations of a statistical mechanics model with hyperbolic symmetry. This talk will describe and analyze a simpler version of this model which is closely related to random walk...