The Abraham–Minkowski controversy is a physics debate concerning electromagnetic momentum within dielectric media. Two equations were first suggested by Hermann Minkowski (1908) Wikisource translation: The Fundamental Equations for Electromagnetic Processes in Moving Bodies and Max Abraham (1909) Wikisource translation: On the Electrodynamics of Moving Bodies Wikisource translation: On the Electrodynamics of Minkowski for this momentum. They predict different values, from which the name of the controversy derives. See also: Experimental support has been claimed for both. Physicist Vitaly Ginzburg called it a perpetual problem.
The two points of view have different physical interpretations and thus neither need be more correct than the other. David J. Griffiths argues that, in the presence of matter, only the total stress–energy tensor carries unambiguous physical significance; how one apportions it between an "electromagnetic" part and a "matter" part depends on context and convenience.
Several papers have claimed to have resolved this controversy.
The controversy is still claimed to have importance in physics beyond the Standard Model where electrodynamics gets modifications, like in the presence of axions.
Equations In SI units, the equations describe electromagnetic momentum and are given by +MinkoskwiAbraham
where: is the density of electromagnetic momentum is the electric displacement field is the magnetic flux density
is the electric field is the magnetizing field is the speed of light squared
Consequences According to Abraham, the momentum of an electromagnetic wave in a medium should be slower. Minkowski predicts that the momentum should be larger.
For a finite-length optical fiber emitting light at one of its ends, it is unclear if the fiber recoils backs in the direction of the light emission (as predicted by Abraham) or if the fiber is pulled in the direction of emission (as predicted by Minkowski).
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