文摘
We consider the damped wave equation with Dirichlet boundary conditions on the unit square parametrized by Cartesian coordinates x and y. We assume the damping a to be strictly positive and constant for \(x<\sigma \) and zero for \(x>\sigma \). We prove the exact \(t^{-4/3}\)-decay rate for the energy of classical solutions. Our main result (Theorem 1) answers question (1) of Anantharaman and Léautaud (Anal PDE 7(1):159–214, 2014, Section 2C).