Spectra for Semiclassical Operators with Periodic Bicharacteristics in Dimension Two
Spectra for Semiclassical Operators with Periodic Bicharacteristics in Dimension Two
We study the distribution of eigenvalues for selfadjoint |$h$|-pseudodifferential operators in dimension two, arising as perturbations of selfadjoint operators with a periodic classical flow. When the strength |$\varepsilon$| of the perturbation is |$\ll h$|, the spectrum displays a cluster structure, and assuming that |$\varepsilon \gg h^2$| (or sometimes |$\gg h^{N_0}$|, …