An example of a periodic magnetic Schrödinger operator with degenerate lower edge of the spectrum
Roman Shterenberg · St Petersburg Mathematical Journal · 2005
The structure of the lower edge of the spectrum of a periodic magnetic Schrödinger operator is investigated. It is known that in the nonmagnetic case the energy depends quadratically on the quasimomentum in a neighborhood of the lower edge of the spectrum of the operator. An example of a magnetic Schrödinger operator is constructed for which energy is partially degenerate with respect to one component of the quasimomentum.