BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Karyn Le Hur (Centre de Physique Theorique\, École Polytechnique\ , CNRS) DTSTART:20210503T160000Z DTEND:20210503T170000Z DTSTAMP:20260423T021426Z UID:QM3/43 DESCRIPTION:Title: Geo metry\, Light Response and Quantum Transport in Topological States of Matt er\nby Karyn Le Hur (Centre de Physique Theorique\, École Polytechniq ue\, CNRS) as part of Quantum Matter meets Maths (IST\, Lisbon)\n\n\nAbstr act\nTopological states of matter are characterized by a gap in the bulk o f the system referring to an insulator or a superconductor and topological edge modes as well which find various applications in transport and spint ronics. The bulk-edge correspondence is associated to a topological number . The table of topological states include the quantum Hall effect and the quantum anomalous Hall effect\, topological insulators and topological sup erconductors in various dimensions and lattice geometries. Here\, we discu ss classes of states which can be understood from mapping onto a spin-1/2 particle in the reciprocal space of wave-vectors. We develop a geometrical approach on the associated Poincare-Bloch sphere\, developing smooth fiel ds\, which shows that the topology can be encoded from the poles only. We show applications for the light-matter coupling when coupling to circular polarizations and develop a relation with quantum transport and the quantu m Hall conductivity. The formalism allows to include interaction effects. We show our recent developments on a stochastic approach to englobe these interaction effects and discuss applications for the Mott transition of th e Haldane and Kane-Mele models. Then\, we develop a model of coupled spher es and show the possibility of fractional topological numbers as a result of interactions between spheres and entanglement allowing a superposition of two geometries\, one encircling a topological charge and one revealing a Bell or EPR pair. Then\, we show applications of the fractional topologi cal numbers C=1/2 in bilayer honeycomb models describing topological semi- metals characterized by a quantized Berry phase at one Dirac point.\n\n- J oel Hutchinson and Karyn Le Hur\, arXiv:2002.11823 (under review)\n\n- Phi lipp Klein\, Adolfo Grushin\, Karyn Le Hur\, Phys. Rev. B 103\, 035114 (20 21)\n LOCATION:https://researchseminars.org/talk/QM3/43/ END:VEVENT END:VCALENDAR