Akce ČVUT

Kvantový kroužek ONLINE: Pavel Exner - Spiral quantum waveguides

10.11.2020   14:45

Srdečně vás zveme na první listopadový seminář v rámci Kvantového kroužku a vůbec první Kvantový kroužek ONLINE. Prostřednictvím platformy Zoom bude hovořit prof. RNDr. Pavel Exner, DrSc. (FJFI) na téma Spiral quantum waveguides. Seminář se koná v úterý 10. 11. 2020 od 14.45 hod. Zoom-ové souřadnice, které vám umožní se semináře zúčastnit, najdete na webu Kvantového kroužku (viz níže).

Abstract:
The topic of this talk is a quantum particle confined to a spiral-shaped region with Dirichlet boundary. As a case study we analyze in detail the Archimedean spiral and show that the spectrum above the continuum threshold is absolutely continuous away from the thresholds. The subtle difference between the radial and perpendicular width implies, however, that in contrast to numerous examples of 'less curved' waveguides, the discrete spectrum is empty in this case. We also discuss modifications such a multi-arm Archimedean spirals and spiral waveguides with a central cavity; in the latter case bound state already exist if the cavity exceeds a critical size. For spiral regions of a more general type the spectral nature depends substantially on whether their coil width is 'expanding' or 'shrinking'. The most interesting situation occurs in the case we call asymptotically Archimedean, where the existence of bound states depends on the direction from which the asymptotics is reached.

Kontaktní osoba

prof. RNDr. Pavel Exner, DrSc.

Podrobnější informace

http://gemma.ujf.cas.cz/%7Eexner/qc.html