Mathematical Physics and Operator Algebras

•  Alberto Takase, MSU and UC Irvine
•  Spectral estimates of dynamically-defined and amenable operator families (In collaboration with Siegfried Beckus)
•  09/20/2022
•  11:00 AM - 11:50 AM
•  C304 Wells Hall
•  Ilya Kachkovskiy (ikachkov@msu.edu)

For dynamically-defined operator families, the Hausdorff distance of the spectra is estimated by the distance of the underlying dynamical systems while the group is amenable. We prove that if the group has strict polynomial growth and both the group action and the coefficients are Lipschitz continuous, then the spectral estimate has a square root behavior or, equivalently, the spectrum map is $\frac{1}{2}$-Holder continuous. We prove the behavior can be improved resulting in the spectrum map being Lipschitz continuous if the coefficients are locally-constant. In 1990, the square root behavior was established for the Almost Mathieu Operator or, more generally, the quasiperiodic operators with Lipschitz continuous potentials. Our results extend the square root behavior to a bigger class of operators such as (magnetic) discrete Schrodinger operators with finite range and with Lipschitz continuous coefficients.

Contact

Department of Mathematics
Michigan State University