Rigidity for the heat equation with density on Riemannian manifolds through a conformal change
Alexander Asaturovich Grigor'yan, Giulia Meglioli, Alberto Roncoroni · arXiv (Cornell University) · 2025
We investigate uniqueness of solution to the heat equation with a density $ρ$ on complete, non-compact weighted Riemannian manifolds of infinite volume. Our main goal is to identify sufficient conditions under which the solution $u$ vanishes identically, assuming that $u$ belongs to a certain weighted Lebesgue space with exponential or polynomial weight, $L^p_ϕ$. We distinguish between the cases $p > 1$ and $p = 1$ which required stronger assumptions on the manifold and the density function $ρ$. We develop a unified method based on a conformal transformation of the metric, which allows us to reduce the problem to a standard heat equation on a suitably weighted manifold. In addition, we construct explicit counterexamples on model manifolds which demonstrate optimality of our assumptions on the density $ρ$.