1207.2271 (Pavel Exner et al.)

Strong coupling asymptotics for a singular Schroedinger operator with an
interaction supported by an open arc    [PDF]

Pavel Exner, Konstantin Pankrashkin

We consider a singular Schr\"odinger operator in $L^2(\RR^2)$ written formally as $-\Delta - \beta\delta(x-\gamma)$ where $\gamma$ is a $C^4$ smooth open arc in $\RR^2$ of length $L$ with regular ends. It is shown that the $j$th negative eigenvalue of this operator behaves in the strong-coupling limit, $\beta\to +\infty$, asymptotically as \[ E_j(\beta)=-\frac{\beta^2}{4} +\mu_j +\cO\Big(\dfrac{\log\beta}{\beta}\Big), \] where $\mu_j$ is the $j$th Dirichlet eigenvalue of the operator \[ -\frac{d^2}{ds^2} -\frac{\kappa(s)^2}{4}\, \] on $L^2(0,L)$ with $\kappa(s)$ being the signed curvature of $\gamma$ at the point $s\in(0,L)$.

View original: http://arxiv.org/abs/1207.2271