Regarding the Abraham tensor, Møller indicated that for a plane light wave propagating in an isotropic uniform medium, observed in the medium-rest frame the Abraham tensor produces an Abraham force, given by formula_44, but "the electromagnetic energy is conserved", namely there is no energy exchange between the light wave and the medium; however, observed in a moving inertial frame, there is "an exchange of energy between the electromagnetic and the mechanical system, i.e. a local absorption and re-emission of light energy by the body material". According to the principle of relativity, Møller argues that Minkowski tensor "is more natural" than Abraham tensor. However Brevik disagrees, arguing that "the Abraham force fluctuates out" for an optical pulse; and he proposed an interesting experiment to detect this Abraham force, predicting "if this idea could be realized experimentally, it would be the first case that the Abraham force is detected explicitly in optics". Brevik's prediction implies that the Abraham momentum, which was first assumed by Abraham, has never been confirmed by experiments so far, although experimental observations of Abraham momentum have been already claimed by several research groups.