Seminars Sorted by Series
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...
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...
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...
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...
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...
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)...
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...
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...
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...
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.
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...
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...
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"...
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...
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...
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...
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...
6:00pm|Birch Garden, Simons Hall
Mathematical Physics Seminar
Conformal Invariance and the Diffusion on Moduli Space for Radial SLE
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...
Matrix Models, Random Partitions, Planar Graphs and Random Surfaces
"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...
Seiberg-Witten Theory and Random Partitions
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...
Large Deviations for a Point Process of Bounded Variability
Eugene Speer
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...
Jamming and k-core Percolation
Andrea Liu
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...
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...
Matrix Models for Random Circular Ensembles
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...
Universality for Orthogonal and Symplectic Ensembles
Percy Deift
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...
Lowest Energy States in Non-Relativistic QED
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...
Edge and Bulk Currents in 2D Disordered Magnetic Systems
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...
Resonances and Formation of the Gaps in the Spectrum of Quasi-Periodic Schrödinger Equation
3:00pm|Fine Hall 314, Princeton University
Ionization in Time Periodic Fields of Arbitrary Strength: The Hydrogen Atom
The Thermodynamics Pressure of a Dilute Fermi Gas
Robert Seiringer
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...
Nonequilibrium Stationary States: An Overview
On the Fourier Law for Coupled Oscillators
Anti Kupiainen
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.
Blow Ups in Complex Solutions of the 3D-Navier-Stokes System and Renormalization Group Method
Yakov Sinai
Droplet Minimizers for Free Energy Functionals with a Liquid-Vapor Transition at the Droplet Formation Threshold
Eric Carlen
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...
Microscopic Models for Thermal Conductivity
Stefano Olla
Directed Polymers with Quenched Randomness: Delocalization Transition and Critical Properties
Fabio Toninelli
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...
Cardy's Formula for Certain Models of the Bond-Triangular Type
Lincoln Chayes
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.
On the Connection Between SLE and CFT
Critical 2d Models on the Annulus
John Cardy
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.
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...
The Renormalisation Group II
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...
The Natural Parametrization for the Schramm-Loewner Evolution
Greg Lawler
Random Conformal Snowflakes
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...
Optimal Transport and Geometric Inequalities
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...
Full Regularity for the Dissipative Quasi-Geostrophic Equations
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...
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...
Transfer Matrix Methods for Discrete Schroedinger Operators
Hermann Schulz-Baldes
Large Deviations of the Current in Non-Equilibrium Systems
Thierry Bodineau
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...
A Statistical Mechanics Model of Random Matrices
Tom Spencer
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...