Bounds on the number of scattering poles of half-Laplacian in odd dimensions, $d\geq 3$

Abstract

We study the scattering poles of $\sqrt{-\Delta} + V$, where $V$ is a compactly supported, bounded and complex valued potential. We show that the resolvent operator $ \chi R_V \chi$ has a meromorphic continuation to the whole Riemannian surface of $\Lambda$ of $ \log z $ as an operator $L^2 \to L^2 $. We then obtain the upper bound on the counting function $N(r,a)= \# \{ z_j \in \Lambda: 0 \leq |z_j| \leq r, |\arg z_j| \leq a \}$, $r >1$, $ |a| >1$ as $C \langle a \rangle ( \langle r \rangle^{d} + (\log \langle a \rangle)^d) $, where $z_j$ are the poles of $ \chi R_V \chi$.