Convergence of kinetic Langevin samplers for non-convex potentials

We study three kinetic Langevin samplers including the Euler discretization, the BU and the UBU splitting scheme. We provide contraction results in $L^1$-Wasserstein distance for non-convex potentials. These results are based on a carefully tailored distance function and an appropriate coupling construction. Additionally, the error in the $L^1$-Wasserstein distance between the true target measure and the invariant measure of the discretization scheme is bounded. To get an $\epsilon$-accuracy in $L^1$-Wasserstein distance, we show complexity guarantees of order $\mathcal{O}(\sqrt{d}\mathrm{/}\epsilon )$ for the Euler scheme and $\mathcal{O}(d^{1\mathrm{/}4}\mathrm{/}\sqrt{\epsilon })$ for the UBU scheme under appropriate assumptions on the target measure. The results are applicable to interacting particle systems and provide bounds for sampling probability measures of mean-field type.