One dimensional quantum Ising model and hyperbolic dynamics

Speaker: 

William Yessen

Institution: 

UC Irvine

Time: 

Tuesday, October 12, 2010 - 3:00pm

Location: 

RH 440R

The one dimensional quantum Ising model is used in quantum statistical physics to model interracting particles on a discrete lattice. While the classical model (in one and two dimensions) has long been solved (its origin dates back to 1930's), its quasiperiodic analog (dating back about 25 years) is still a source of interesting problems. We shall discuss our solution to one such problem: we'll rigorously prove that the energy spectrum of the one dimensional quantum quasiperiodic Ising model is a Cantor set, as has been long believed, and discuss some of its properties.
This is the first in a series of two seminars dedicated to this topic. In this seminar we'll present the problem and set up the main ideas.

On conservative homoclinic bifurcations: recent results and open problems

Speaker: 

Anton Gorodetski

Institution: 

UC Irvine

Time: 

Tuesday, October 5, 2010 - 3:00pm

Location: 

RH 440R

In 1970s S.Newhouse discovered that a generic homoclinic bifurcation of a smooth surface diffeomorphism leads to persistent homoclinic tangencies, infinite number of attractors (or repellers), and other unexpected dynamical properties (nowadays called "Newhouse phenomena"). More than 20 years later P.Duarte provided an analog of these results in conservative setting (with attractors replaced by elliptic periodic points). We will discuss these and other recent results on conservative homoclinic bifurcations, and list some related open problems in the field.

On one-dimensional Schrodinger Operator with potential given by Period Doubling and Thue-Morse sequences.

Speaker: 

Vinod Sastry

Institution: 

UC Irvine

Time: 

Friday, June 4, 2010 - 2:00pm

Location: 

RH 440R

We consider the one-dimensional Schrodinger operator with potential given by Period Doubling and Thue-Morse sequences. We describe the results of Bellisard et al. in which the spectrum of these operators are obtained through the trace map associated to this operator. We see that the spectrum for non-zero values of the potential is a Cantor set of zero Lebesque measure, and give explicit description of the spectral gaps.

Application of trace map techniques to 1D Ising models, II

Speaker: 

William Yessen

Institution: 

UC Irvine

Time: 

Friday, April 23, 2010 - 2:00pm

Location: 

RH 440R

We consider the classical 1D Ising model, where the coupling constants and the external magnetic field take one of two possible values at each site, according to a substitution rule. We shall introduce (briefly) the idea of a trace map corresponding to the given substitution rule and how its dynamical properties can be used to investigate the partition function and, consequently, the free energy function of the given Ising model.

Application of trace map techniques to 1D Ising models

Speaker: 

William Yessen

Institution: 

UC Irvine

Time: 

Friday, April 16, 2010 - 2:00pm

Location: 

RH 440R

We consider the classical 1D Ising model, where the coupling constants and the external magnetic field take one of two possible values at each site, according to a substitution rule. We shall introduce (briefly) the idea of a trace map corresponding to the given substitution rule and how its dynamical properties can be used to investigate the partition function and, consequently, the free energy function of the given Ising model.

Pages

Subscribe to RSS - Dynamical Systems