Résumé : In the first part of my talk, I will show that a quantum system with translational invariance may host dispersionless wave packets and that a sufficient condition for their existence is presence of a linear energy band in the spectrum of the corresponding Hamiltonian. This condition is, of course, very restrictive, so we will also briefly study what happens if it is slightly violated. Still, there are some rare examples of systems with exactly linear bands – those I am aware of are always governed by 2D Dirac Hamiltonian. In the second part of my talk, I will show how to construct a new example of such a system employing some basic self-adjoint extension techniques.
Lieu : Salle 3L15, IMO (Bâtiment 307)
Département de Mathématiques
Bâtiment 307
Faculté des Sciences d'Orsay Université Paris-Sud F-91405 Orsay Cedex Tél. : +33 (0) 1-69-15-79-56 
Département
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