Category: Uncategorized

Carolina Canales Gonzalez (28/02/2019)

Valentina Giangreco, febrúar 25, 2019

Málstofa í stærðfræði

Fyrirlesari: Carolina Canales Gonzalez, Pontificia Universidad Católica de Chile

Titill: Looking for a complex Poincaré-Bendixson theorem

Staðsetning: V-258, VR-II
Tími: Fimmtudagur 28. febrúar kl. 11.40

Ágrip:

The goal of this talk is to introduce the study of holomorphic foliations.

First, we will recall some things about differential equations on $\mathbb{R}^2$, like the Poincaré-Bendixson theorem and Hilbert’s 16th problem and then we will pass to the complex context where we will introduce holomorphic foliations.

The idea is to talk about the problem of the exceptional minimal set, who is an analog of Poincaré-Bendixson theorem in this new context, and about the developments in complex geometry, analysis and dynamics related with the study of this problem.

Carlos Argaez Garcia

Valentina Giangreco, febrúar 15, 2019

Málstofa í stærðfræði

Fyrirlesari: Carlos Argaez Garcia, Háskóli Íslands

Titill: Numerical methods for dynamic systems: Analysis of stability

Staðsetning: V-258, VR-II
Tími: Fimmtudagur 21. febrúar kl. 11.40

Ágrip:

Dynamic systems describe the evolution over time of quantities governed by
differential equations. Therefore they are a powerful descriptive tool of
phenomena originated in applied disciplines.
A  complete Lyapunov  function describes the dynamic behavior of such
systems without requiring the explicit solution of the differential
equations. However, these have the disadvantage of being difficult to
obtain.
The algorithms proposed here, reduce the effort to obtain such functions
and even more, are able to isolate the regions whose dynamics have a
periodic behavior.
Throughout this talk, simple examples of applications in both two- and
three-dimensional systems will be given.

Jens H. Bárðarson (04/12/2018)

Valentina Giangreco, nóvember 29, 2018

Math Phys/Phys seminar

Fyrirlesari: Jens H. Bárðarson, KTH Stockholm

Titill: On the chiral anomaly in Weyl semimetals

Staðsetning: VR-II 158
Tími:þriðjudagur 4. desember, kl. 13.30

Ágrip:

I will give an introduction to the physics of Weyl semimetals focussing on Fermi arcs and chiral anomaly. I will then discuss some transport properties of Weyl semimetals including strongly angular-dependent magnetotransport in the presence of long range disorder, and the difference between the longitudinal conductance in the presence of magnetic field and chiral pseudo-magnetic field. The latter points in opposite direction for opposite chiralities and can be induced, for example, by strain. This leads to a discussion of pseudo-landau levels and their connection with Fermi arcs and covariant and consistent chiral anomaly. I will also mention a new axial torsional contribution to the axial anomaly.