Controllability of the Schrödinger equation on unbounded domains without geometric control condition

M Täufer - ESAIM: Control, Optimisation and Calculus of …, 2023 - esaim-cocv.org
We prove controllability of the Schrödinger equation in ℝ d in any time T> 0 with internal
control supported on nonempty, periodic, open sets. This demonstrates in particular that …

Unique continuation and lifting of spectral band edges of Schrödinger operators on unbounded domains

I Nakić, M Täufer, M Tautenhahn, I Veselić - Journal of Spectral Theory, 2020 - ems.press
We prove and apply two theorems: first, a quantitative, scale-free unique continuation
estimate for functions in a spectral subspace of a Schrödinger operator on a bounded or …

Null-controllability and control cost estimates for the heat equation on unbounded and large bounded domains

M Egidi, I Nakić, A Seelmann, M Täufer… - Control theory of infinite …, 2020 - Springer
We survey recent results on the control problem for the heat equation on unbounded and
large bounded domains. First we formulate new uncertainty relations, respectively spectral …

Band edge localization beyond regular Floquet eigenvalues

A Seelmann, M Täufer - Annales Henri Poincaré, 2020 - Springer
We prove that localization near band edges of multi-dimensional ergodic random
Schrödinger operators with periodic background potential in L^ 2 (R^ d) L 2 (R d) is …

Magnetic Bernstein inequalities and spectral inequality on thick sets for the Landau operator

P Pfeiffer, M Täufer - arxiv preprint arxiv:2309.14902, 2023 - arxiv.org
We prove a spectral inequality for the Landau operator. This means that for all $ f $ in the
spectral subspace corresponding to energies up to $ E $, the $ L^ 2$-integral over suitable …

Quantitative unique continuation for spectral subspaces of Schrödinger operators with singular potentials

A Dicke, C Rose, A Seelmann, M Tautenhahn - Journal of Differential …, 2023 - Elsevier
Recent (scale-free) quantitative unique continuation estimates for spectral subspaces of
Schrödinger operators are extended to allow singular potentials such as certain L p …

[HTML][HTML] Sampling and equidistribution theorems for elliptic second order operators, lifting of eigenvalues, and applications

M Tautenhahn, I Veselić - Journal of Differential Equations, 2020 - Elsevier
We consider elliptic second order partial differential operators with Lipschitz continuous
leading order coefficients on finite cubes and the whole Euclidean space. We prove …

Unique continuation and lifting of spectral band edges of Schr\" odinger operators on unbounded domains (With an Appendix by Albrecht Seelmann)

I Nakić, M Täufer, M Tautenhahn, I Veselic… - arxiv preprint arxiv …, 2018 - arxiv.org
We prove and apply two theorems: First, a quantitative, scale-free unique continuation
estimate for functions in a spectral subspace of a Schr\" odinger operator on a bounded or …