Abstract:
Applying a quantum mechanical treatment to a high-frequency macroscopic electromagnetic field and radiative phenomena in a medium, we construct quantum operators for energy–momentum tensor components in dispersive media and find their eigenvalues, which are different in the Minkowski and Abraham representations. It is shown that the photon momentum in a medium resulting from the quantization of the vector potential differs from that defined from Abraham's symmetric energy–momentum tensor but is equal to the momentum defined from the Minkowski tensor. A similar result is obtained by calculating the intrinsic angular momentum (spin) of an electromagnetic field in the medium. Only the Minkowski tensor leads to the experimentally confirmed spin values that are multiples of $\hbar$, providing the grounds for choosing the Minkowski representation as the proper form for the momentum density of a transverse electromagnetic field in a transparent medium, in both classical and quantum descriptions of the field. The Abraham representation is unsuitable for this purpose and leads to contradictions. The conclusion drawn does not apply to quasistatic and static fields.
Keywords:Minkowski energy–momentum tensor, quantum theory, radiation phenomena, spin and mass of a photon in matter.
PACS:12.20.-m, 41.20.Jb, 41.60.Bq
Received:June 21, 2016 Revised:April 8, 2017 Accepted: April 12, 2017
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