  In space dimension $n\geq3$, we consider the electromagnetic Schr\"odinger
Hamiltonian $H=(\nabla-iA(x))^2-V$ and the corresponding Helmholtz equation
$(\nabla-iA(x))^2u+u-V(x)u=f \in \mathbb{R}^n$. We extend the well known
$L^p$-$L^q$ estimates for the solution of the free Helmholtz equation to the
case when the electromagnetic hamiltonian $H$ is considered.
