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