日時：12月23日（月）17:00 ～ 18:00
場所：ウエストウイング6階 数理科学科 談話会室
講演者：Rafael Tiedra de Aldecoa 氏（Pontifical Catholic University of Chile）
講演題目：Spectral analysis of quantum walks with an anisotropic coin
講演概要：
We perform the spectral analysis of the evolution operator U of quantum walks with an anisotropic coin, which include one-defect models, two-phase quantum walks, and topological phase quantum walks as special cases. In particular, we determine the essential spectrum of U, we prove the discreteness of the eigenvalues of U outside the thresholds, and we prove the absence of singular continuous spectrum for U. Our analysis is based on new commutator methods for unitary operators in a two-Hilbert spaces setting, which are of independent interest. Joint work with Serge Richard (Nagoya University) and Akito Suzuki (Shinshu University).
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