I am reading this note on potential scattering by Siu-Hung Tang and Maciej Zworski. Just wondering if there is a scattering theory for the Schrödinger with a non-decaying potential $- \Delta + V$ on the real line, like, for some $V$ that has an non-zero asymptote as $|x| \rightarrow \infty$.

Any reference/comment would be great - Thanks in advance!