We determine the invariant expression of the force density that theelectromagnetic field exerts on dipolar matter and construct the non-symmetricenergy-momentum tensor of the electromagnetic field in matter which isconsistent with that force and with Maxwell equations. We recover Minkowski'sexpression for the momentum density. We use our results to discuss momentumexchange of an electromagnetic wave-packet which falls into a dielectric block.In particular we show that the wave-packet pulls the block when it enters anddrags it when it leaves. The usual form of the center of mass motion theoremdoes not hold for this system but a modified version of the theorem whichincludes a spin contribution is shown to be satisfied.
展开▼
