Endpoint Mapping Properties of Wave Operators for Schr\"odinger Operators in Dimensions $n\ge3$
We study endpoint mapping properties of low-energy wave operators for Schr\"odinger operators $H=-\Delta+V$ on $\mathbb R^n$, $n\ge3$. In dimension four, we prove that a zero-energy resonance prevents $L^1$ boundedness, whether or not zero is also an eigenvalue, under $|V(x)|\lesssim\langle x\rangle^{-\beta}$ with $\be...