BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20251227T172540EST-7439mhZxNV@132.216.98.100 DTSTAMP:20251227T222540Z DESCRIPTION:Sharp arithmetic transitions for 1D quasiperiodic operators\n\n A very captivating question in solid state physics is to determine/underst and the hierarchical structure of spectral features of operators describin g 2D Bloch electrons in perpendicular magnetic fields\, as related to the continued fraction expansion of the magnetic flux. In particular\, the hie rarchical behavior of the eigenfunctions of the almost Mathieu operators\, despite significant numerical studies and even a discovery of Bethe Ansat z solutions has remained an important open challenge even at the physics l evel.\n \n I will present a complete solution of this problem in the exponen tial sense throughout the entire localization regime. Namely\, I will desc ribe the continued fraction driven hierarchy of local maxima\, and a unive rsal (also continued fraction expansion dependent) function that determine s local behavior of all eigenfunctions around each maximum\, thus giving a complete and precise description of the hierarchical structure. In the re gime of Diophantine frequencies and phase resonances there is another univ ersal function that governs the behavior around the local maxima\, and a r eflective-hierarchical structure of those\, phenomena not even described i n the physics literature. These results lead also to the proof of sharp ar ithmetic transitions between pure point and singular continuous spectrum\, in both frequency and phase\, as conjectured since 1994. This part of the talk is based on the papers joint with W. Liu.Within the singular continu ous regime\, it is natural to look for further\, dimensional transitions. I will present a sharp arithmetic transition result in this regard that ho lds for the entire class of analytic quasiperiodic potentials\, based on t he joint work with S. Zhang.\n DTSTART:20181116T210000Z DTEND:20181116T220000Z LOCATION:Room 1140\, CA\, Pav. André-Aisenstadt SUMMARY:Svetlana Jitomirskaya\, UC Irvine / Chaire Aisenstadt 2018 URL:/mathstat/channels/event/svetlana-jitomirskaya-uc- irvine-chaire-aisenstadt-2018-291500 END:VEVENT END:VCALENDAR