Sharp low frequency resolvent estimates on asymptotically conical manifolds

On a class of asymptotically conical manifolds, we prove two types of low frequency estimates for the resolvent of the Laplace-Beltrami operator. The first result is a uniform $L^2 \rightarrow L^2$ bound for $\langle r \rangle^{-1} (- \Delta_G - z)^{-1} \langle r \rangle^{-1}$ when $\mbox{Re}(z)$ is small, with the optimal weight $\langle r \rangle^{-1}$. The second one is about powers of the resolvent. For any integer $N$, we prove uniform $L^2 \rightarrow L^2$ bounds for $\langle \epsilon r \rangle^{-N} (-\epsilon^{-2} \Delta_G - Z)^{-N} \langle \epsilon r \rangle^{-N}$ when $\mbox{Re}(Z)$ belongs to a compact subset of $(0,+\infty)$ and $0 < \epsilon \ll 1$. These results are obtained by proving similar estimates on a pure cone with a long range perturbation of the metric at infinity.