Weak Convergence of Finite Element Approximations of Stochastic Linear Schrödinger equation driven by additive Wiener noise
Mangala Prasad
TL;DR
This work studies the weak convergence of spatial finite element approximations for a stochastic linear Schrödinger equation with additive Wiener noise. By formulating a general weak-error framework and employing semigroup and operator-norm estimates, it derives a bound showing the weak convergence rate is twice the strong rate under suitable covariance assumptions on the noise and for test functions in $C^2_b(H,\mathbb{R})$. The approach parallels existing weak-convergence analyses for heat and wave equations and yields practical guidance for accurately computing expected functionals of the solution. The results enhance understanding of SPDE discretizations in quantum-like dispersive systems and have implications for reliable numerical simulations of stochastic Schrödinger dynamics.
Abstract
A standard finite element method discretizes the stochastic linear Schrödinger equation driven by additive noise in the spatial variables. The weak convergence of the resulting approximate solution is analyzed, and it is established that the weak convergence rate is twice that of the strong convergence.
