Relationship between the Einstein-Laub electromagnetic force and the Lorentz force on free charge

[摘要] An electromagnetic force density expression that is consistent with a development attributed to Einstein and Laub appears to be able to describe optical force experiments done to date with homogenized media. However, a major question that has persisted for about one century relates to the apparent discrepancy with the usual interpretation of the force description due to Lorentz in magnetized media. Specifically, it had appeared that the Einstein and Laub force density incorporated only the free-space permeability in relation to the force on the electric current density. It is shown here that the Einstein and Laub force density is consistent with the Lorentz picture in the static limit. This resolves a key impediment in establishing a unified force density description for electromagnetic waves interacting with matter.

[关键词] RADIATION PRESSURE;DIELECTRIC MEDIA;LINEAR MOMENTUM;MICROSCOPY;WAVE;PARTICLES;FIELD