4 papers
On almost commuting unitary matrices
Adam Dor-On, Lucas Hall, Ilya Kachkovskiy
A question going back to Halmos asks when two approximately commuting matrices of a certain kind are close to exactly commuting matrices of the same kind. It has long been known th…
Absence of flat bands for discrete periodic graph operators with generic potentials
Matthew Faust, Ilya Kachkovskiy
We show that Schrödinger-type operators on discrete connected periodic graphs do not have flat bands for generic potentials.
Perturbative diagonalization and spectral gaps of quasiperiodic operators on with monotone potentials
Ilya Kachkovskiy, Leonid Parnovski, Roman Shterenberg
We obtain a perturbative proof of localization for quasiperiodic operators on with one-dimensional phase space and monotone sampling functions, in the regime of smal…
On gaps in the spectra of quasiperiodic Schrödinger operators with discontinuous monotone potentials
Ilya Kachkovskiy, Leonid Parnovski, Roman Shterenberg
We show that, for one-dimensional discrete Schrödinger operators, stability of Anderson localization under a class of rank one perturbations implies absence of intervals in spectr…