Asymptotics of Partial Density Functions for Divisors

Abstract

We study the asymptotic behaviour of the partial density function associated to sections of a positive hermitian line bundle that vanish to a particular order along a fixed divisor $Y$. Assuming the data in question is invariant under an $S^1$-action (locally around $Y$) we prove that this density function has a distributional asymptotic expansion that is in fact smooth upon passing to a suitable real blow-up. Moreover we recover the existence of the "forbidden region" $R$ on which the density function is exponentially small, and prove that it has an "error-function" behaviour across the boundary $\partial R$. As an illustrative application, we use this to study a certain natural function that can be associated to a divisor in a K\"ahler manifold.