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The velocities of light in modified QED vacua
Author(s) -
Scharnhorst K.
Publication year - 1998
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/(sici)1521-3889(199812)7:7/8<700::aid-andp700>3.0.co;2-k
Subject(s) - casimir effect , physics , vacuum state , vacuum energy , qed vacuum , quantum electrodynamics , boundary value problem , quantum fluctuation , homogeneous , front velocity , field (mathematics) , magnetic field , electromagnetic field , group velocity , condensed matter physics , front (military) , quantum mechanics , quantum , mathematics , meteorology , pure mathematics , thermodynamics
QED vacua under the influence of external conditions (background fields, finite temperature, boundary conditions) can be considered as dispersive media whose complex behaviour can no longer be described in terms of a single universal vacuum velocity of light c . Beginning in the early 1950's (J.S. Toll), quantum field theoretic investigations have led to considerable insight into the relation between the vacuum structure and the propagation of light. Recent years have witnessed a significant growth of activity in this field of research. After a short overview, two characteristic situations are discussed: the propagation of light in a constant homogeneous magnetic field and in a Casimir vacuum. The latter appears to be particularly interesting because the Casimir vacuum has been found to exhibit modes of the propagation of light with phase and group velocities larger than c in the low frequency domain ω ≪ m where m is the electron mass. The impact of this result on the front velocity of light in a Casimir vacuum is discussed by means of the Kramers‐Kronig relations.