Statut  Confirmé 
Série  SEMLPTMC 
Domaines  condmat.meshall 
Date  Lundi 14 Octobre 2019 
Heure  10:45 
Institut  LPTMC 
Salle  campus Jussieu, tower 1312, 5th floor, room 523 
Nom de l'orateur  Marciani 
Prenom de l'orateur  Marco 
Addresse email de l'orateur  
Institution de l'orateur  Laboratoire de Physique, ENS Lyon 
Titre  Optical topological chiral modes flowing between nontopological materials 
Résumé  The most remarkable feature of the socalled "topological crystals" is the presence of states flowing at their edge that are robust against disorder. A beautiful mathematical theory allows to predict the properties of such states directly from the topological invariants (e.g. the Chern numbers) of the bulk bands. Given the great success of this theory in terms of theoretical impact and technological advance, in recent years much effort has been put to make the extension from the field electronics to other fields[1] and from crystals to various noncrystaline systems such as quasicrystals and amorphous materials. In this talk I will show how deal with continuous systems governed by linear Maxwell's equations[2]. Even though bands Chern numbers cannot be defined and optical materials are nontopological, we discover that interface Chern numbers can always be defined by means of the theory of spectral flows[3]. These invariants correctly describe chiral modes as we verified numerically on interfaces between different gyrotropic materials. [1] S. Raghu and F. D. M. Haldane, Phys. Rev. A78, 033834 (2008). [2] M. G. Silveirinha, Phys. Rev. B92, 125153 (2015). [3] M. Marciani and P. Delplace, arXiv:1906.09057 (2019). 
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