Exotic diffeomorphisms on closed aspherical $4$-manifolds

Abstract: We study a class of diffeomorphisms of closed manifolds obtained from Davis' reflection trick construction, which are obtained by reflecting a diffeomorphism supported in the fundamental chamber of such a manifold. We use this construction to exhibit the first examples of closed aspherical $4$-manifolds with diffeomorphisms that are topologically isotopic to the identity map, but not smoothly isotopic to it.