This survey is devoted to an exposition of results on the asymptotics of the discrete spectrum of self-adjoint differential operators, mainly partial differential operators.

Asymptotic behavior of the spectrum of differential equations

Planck's radiation law for finite cavities and related problems

A review is presented of various recent investigations on the classical optical radiation laws in the light of the modern concepts of coherence and statistical optics. Temporal coherence of black-body radiation, spatial coherence of Lambertian and non-Lambertian sources, and the interaction of matter with radiation of any state of coherence are emphasized.

Coherence and the radiation laws

Oscillatory spectral density and partial coherence of blackbody radiation in cuboidal cavities

Accurate analytical expressions for the state densities of liquid $^{4}\mathrm{He}$ droplets are derived, incorporating the ripplon and phonon degrees of freedom. The microcanonical temperature and the ripplon angular momentum level density are also evaluated. The approach is based on inversions and systematic expansions of canonical thermodynamic properties.

http://physics.gu.se/~klavs/papers/PRB-2007-He.pdf

H.P. Baltes

Papers

Progress in Weyl's problem achieved by computational methods☆