Julio H. Toloza
Exponentially Accurate Error Estimates of Quasiclassical Eigenvalues
(271K, Postscript)

ABSTRACT.  We study the behaviour of truncated Rayleigh-Schr\"odinger series for 
the low-lying eigenvalues of the one-dimensional, time-independent 
Schr\"odinger equation, in the semiclassical limit $\hbar\rightarrow 0$. 
Under certain hypotheses on the potential $V(x)$, we prove that for any 
given small $\hbar>0$ there is an optimal truncation of the series for 
the approximate eigenvalues, such that the difference between an 
approximate and exact eigenvalue is smaller than $\exp(-C/\hbar)$ for 
some positive constant $C$. We also prove the analogous results 
concerning the eigenfunctions.