Spin is not a moment of momentum
Mathematics. Physics. Mechanics
Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia
AbstractThe modern idea that spin of an electromagnetic radiation is a moment of a linear momentum seems to be incorrect. This fact is of great importance for calculating the torque, which experiences an absorber of a circularly polarized electromagnetic beam. We show that the classical monographs of Jackson and Becker contain inaccurate calculation in the case of a radiation produced by a source localized in a finite region of space. We use a spin tensor introduced into the electrodynamics previously when calculating the total torque.
Keywords:spin tensor, Belinfante-Rosenfeld procedure