High energy asymptotics and trace formulae for the perturbed harmonic   oscillator
  A one-dimensional quantum harmonic oscillator perturbed by a smooth compactly supported potential is considered. For the corresponding eigenvalues $\lambda_n$, a complete asymptotic expansion for large $n$ is obtained, and the coefficients of this expansion are expressed in terms of the heat invariants. A sequence of trace formulas is obtained, expressing regularised sums of integer powers of eigenvalues $\lambda_n$ in terms of the heat invariants. 
Alexander Pushnitski and Ian Sorrell