Spectral estimates for Dirichlet Laplacians and Schroedinger operators   on geometrically nontrivial cusps
  The goal of this paper is to derive estimates of eigenvalue moments for Dirichlet Laplacians and Schr\"odinger operators in regions having infinite cusps which are geometrically nontrivial being either curved or twisted; we are going to show how those geometric properties enter the eigenvalue bounds. The obtained inequalities reflect the essentially one-dimensional character of the cusps and we give an example showing that in an intermediate energy region they can be much stronger than the usual semiclassical bounds. 
Pavel Exner and Diana Barseghyan
math-ph math.MP math.SP quant-ph