LAUSR

The classic electromagnetic energy–momentum problem in matter (usually called the Abraham–Minkowski problem) has attracted increased interest, as is natural in relation to the several impressive radiation pressure experiments that have appeared recently. Our intention with the present note is to focus attention on some of these results, and also to give a warning against premature interpretations of the observations. One sees often in the literature that the observable deflections of dielectric surfaces are interpreted so as to mean that the so-called Abraham term is a chief ingredient. Usually this is not so, however. Most of the experimental results are actually explainable by the surface forces at the dielectric surfaces, eventually augmented by Lorentz forces in the interior, and do not involve the Abraham momentum as such. For concreteness we focus mainly on a simplified version of the experiment of Kundu et al. (2017), but extend the analysis somewhat by including time-dependent resonance phenomena. In a short appendix we discuss also the connection with the Casimir effect.