# Events Archive

## Mathematical Physics Seminar

### Math Physics Seminar, Saidakhmat Lakaev, "Threshold effects of the two and three-particle Schroedinger operators on lattices"

Tue, Apr 8, 2014, 4:30 pm to 5:30 pm

Efimov's effect for a system of three particles moving on three-dimensional lattice and interacting via pairwise short-range potentials is studied. The following new results will be presented:

### Math Physics Seminar, Benjamin Schlein, "From BCS-theory to the Gross-Pitaevskii equation for the evolution of dilute fermion pairs"

Tue, Mar 25, 2014, 4:30 pm to 6:00 pm

We consider a system of fermions interacting through a potential admitting a bound state in the low density limit.
Assuming the energy to be sufficiently small, we show that particles form pairs, exhibiting Bose-Einstein condensation and evolving according to the time-dependent Gross-Pitaevskii equation.

### Math Physics Seminar, Vojkan Jaksic, "Entropic Functionals in Quantum Statistical Mechanics"

Tue, Mar 4, 2014, 4:30 pm to 5:30 pm

The mathematical theory of non-equilibrium quantum statistical mechanics has developed rapidly in the last decade.

### Math Physics Seminar, Jakob Yngvason, Quantum Hall Phases, plasma analogy and incompressibility estimates"

Tue, Feb 25, 2014, 4:30 pm to 5:30 pm

When a 2D many-particle system with a repulsive interaction is subject to a suff iciently strong magnetic field, that can also be produced by rapid rotation, str ongly correlated many-body states in the lowest Landau level LLL may emerge.

### Math Physics Seminar, Eric Carlen, "Remainder terms for some entropy inequalities and entanglement for fermions"

Tue, Feb 18, 2014, 4:30 pm to 5:30 pm

A number of entropy inequalities have proved useful for quantifying the degree of entanglement of bipartite (or multipartite) quantum states.

### Math Physics Seminar, Juerg Froehlich, "Physical Principles Underlying the Fractional Quantum Hall Effect"

Tue, Feb 11, 2014, 4:30 pm to 5:30 pm

I review an approach to the theory of the Quantum Hall Effect (QHE) somewhat analogous to Landau's theory of phase transitions. After a short recapitulation of some of the discoveries leading to the QHE, I describe some of the main experimental facts and data and speculate about possible applications.

### Math Physics Seminar, Volker Bach, "On the Bogolubov-Hartree-Fock (BHF) Approximation for the Pauli-Fierz Model"

Tue, Dec 3, 2013, 4:30 pm to 6:00 pm

The minimal energy of the nonrelativistic one-electron Pauli-Fierz model within the class of quasifree states is studied. It is shown that this minimum is unchanged if one restricts the variation to pure quasifree states, which simplifies the variational problem considerably.

### Math Physics Seminar, Nicolas Rougerie, "Structure of large bosonic systems: the mean-field approximation and the quantum de Finetti theorem"

Tue, Nov 12, 2013, 4:30 pm to 5:00 pm

I will discuss a general strategy to derive Hartree's theory for the ground state of a generic interacting many-bosons system with mean-field scaling. The validity of the mean-field approximation is interpreted as a consequence of the structure of the set of bosonic density matrices with large number of particles, in particular of the so-called...

### Math Physics Seminar, Yoshiko Ogata, "The Quantum Shannon-McMillan theorem and rank of spectral projections of macroscopic observables"

Tue, Oct 15, 2013, 4:30 pm to 5:30 pm

The classical Shannon-McMillan theorem states that an ergodic system has typical sets satisfying the asymptotic equipartition property.
This theorem demonstrates the significance of entropy which gives the size of the typical sets.

### **RESCHEDULED to 10/15/13** Math Physics Seminar -- Yoshiko Ogata .

Tue, Oct 8, 2013, 4:30 pm to 5:30 pm

### Math Physics Seminar, Ajay Chandran, "Construction and Analysis of a hierarchical massless QFT"

Tue, Oct 1, 2013, 4:30 pm to 6:00 pm

l also show how methods from statistical mechanics can be used to prove the full scale invariance of this QFT. (Joint work with Abdelmalek Abdesselam and Gianluca Guadagni.)

### Math Physics Seminar, Alessandro Giuliani, University of Rome, Striped states at the ferromagnetic transition

Tue, May 7, 2013, 4:30 pm to 6:00 pm

We consider a two-dimensional Ising model with nearest neighbor ferromagnetic and long-range, power-law decaying, antiferromagnetic interactions. We assume that the decay exponent of the antiferromagnetic part is larger than 4.

### Math Physics Seminar, Hugo Duminil, U of Geneva, Parafermionic observables in planar Potts models and Self Avoiding Walks

Tue, Apr 30, 2013, 4:30 pm to 6:00 pm

In this talk, we will discuss the role of parafermionic observables in the study of several planar statistical physics models. These objects have been introduced recently by Smirnov and Cardy and have been instrumental in Smirnov's proof of conformal invariance of the Ising model.

### Math Physics Seminar - Vieri Mastropietro, Univ of Milan, Italy, Universal finite size corrections and the central charge in non solvable Ising models

Tue, Apr 16, 2013, 4:30 pm to 6:00 pm

We investigate a non solvable two-dimensional ferromagnetic Ising model with nearest neighbor plus weak finite range interactions. We rigorously establish one of the predictions of Conformal Field Theory (CFT), namely the fact that at the critical temperature the finite size corrections to the free energy are universal.

### Mathematical Physics Seminar - Ron Peled, Tel Aviv University - Surface depinning under the two-dimensional hammock potential

Tue, Apr 2, 2013, 4:30 pm to 6:00 pm

We consider a random two-dimensional surface satisfying a Lipschitz constraint. The surface is uniformly chosen from the set of all real-valued Lipschitz functions on a two-dimensional discrete torus. Our main result is that the surface delocalizes, having fluctuations whose variance is at least logarithmic in the size of the torus.

### Mathematical Physics Seminar - Antti Knowles, Courant Institute - Quantum diffusion and delocalization for random band matrices

Tue, Mar 5, 2013, 4:30 pm to 6:00 pm

I give a summary of recent progress in establishing the diffusion approximation for random band matrices. We obtain a rigorous derivation of the diffusion profile in the regime W > N^{4/5}, where W is the band width and N the dimension of the matrix. As a corollary, we prove complete delocalization of the eigenvectors.

### Cancelled: Math Physics Seminar - Jakob Yngvason, University of Vienna - Interacting Bosons in a Random Potential

Tue, Feb 26, 2013, 4:30 pm to 6:00 pm

We study the effects of random scatterers on the ground state of the one-dimensional Lieb-Liniger model of interacting bosons in the Gross-Pitaevskii regime.

### Math Physics Seminar - Frank Hansen, Tohoku University - Quantum Information Functionals

Tue, Feb 19, 2013, 4:30 pm to 6:00 pm

Quantum information functionals and their algebraic properties play an important role in quantum information theory. Recent developments in the theory of operator monotone and operator convex functions and related topics have simplified earlier results and also led to new insights. One example is the convexity of chi-square divergences.

### CANCELLED Math Physics Seminar - Vojkan Jaksic, McGill University - Quantum Hypothesis Testing and Non-Equilibrium Statistical Mechanics

Tue, Feb 12, 2013, 4:30 pm to 6:00 pm

Since the days of Chernoff, the hypothesis testing has played an important role in theoretical and applied statistics.

### High Energy Theory Seminar - IAS - Kevin Costello, Northwestern University - “Yangians and Supersymmetric Gauge Theory”

Mon, Feb 4, 2013, 2:30 pm to 4:00 pm

I'll describe a new link between supersymmetric gauge theories, with gauge group G, and the Yangian for the Lie algebra of G. The main result is that a certain twisted, deformed N=1 supersymmetric gauge theory, with gauge group G, is "controlled" by the Yangian built from G, in the same way that Chern-Simons theory is controlled by the quantum...