Canonical systems whose Weyl coefficients have dominating real part

Matthias Langer, Raphael Pruckner, Harald Woracek

For a two-dimensional canonical system $y^{\prime }(t)=zJH(t)y(t)$ on the half-line $(0,\infty )$ whose Hamiltonian $H$ is a.e. positive semi-definite, denote by $q_H$ its Weyl coefficient.…