Séminaire: Problèmes Spectraux en Physique Mathématique


Année 2023-2024



Pour tout renseignement complémentaire, veuillez contacter les organisateurs,Hakim Boumaza, Mathieu Lewin ou Stéphane Nonnenmacher.

Prochain séminaire le lundi 18 mars 2024 après-midi à l'Institut Henri Poincaré, en salle Maryam Mirzakhani (2e étage, ex-201)


14h - 15h Bérangère Delourme (Paris-Nord)
Guided waves in honeycomb periodic structures

Abstract:

In this talk, we investigate the propagation of waves in a particular honeycomb structure made of thin tubes.  Based on an asymptotic analysis, we prove that the dispersion surfaces associated with this system  have conical points located at the vertices of the Brillouin zone: this is a well-known property for systems  having hexagonal symmetry. Then, introducing so-called zig-zag perturbations in the structure  generates guided waves propagating along the defect. More  specifically, we show that the frequency of those guided modes may be independent of the quasi-periodicity parameter, leading to almost flat dispersion curves. We present numerical results to illustrate our results.


 15h15 - 16h15 Asbjorn Bækgaard Lauritsen (IST Austria)
Energies of dilute spin-polarized Fermi gasses

Abstract:
Recently the study of dilute quantum gases have received much interest, in particular regarding their ground state energies and pressures/free energies at positive temperature. I will present recent work on such problems concerning that of the ground state energy of a spin-polarized Fermi gas and the extension to the pressure at positive temperature. Compared to the free gas, the energy density/pressure of the interacting gas differs by a term of order a3 ρ8/3, with a the p-wave scattering length of the interaction.

This talk is based on joint work with Robert Seiringer.


Prochaines séances :

22 avril 2024: Henrik Ueberschär, Vojkan Jaksic
13 mai 2024: Frédéric Klopp
17 juin 2024:

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Dernière mise à jour: 12 janvier 2024
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