Consider the wave equation $$ y_{tt} = \Delta y - \epsilon y_t $$

on $\Omega\subset R^n$, with Dirichlet boundary conditions. Where $\epsilon >0$.

Is it possible to find an explicit value $\sigma=\sigma(\epsilon ) > 0$ such that the solution $(y,y_t)$ verifies the estimate

$$ \|(y,y_t)\| \le M e^{-\sigma t} $$