K. Scharnhorst: *The velocities of light in modified QED vacua*.
Annalen der Physik (Leipzig), 8. Series, **7**(1998)700-709
[hep-th/9810221]
(DOI: 10.1002/(SICI)1521-3889(199812)7:7/8<700::AID-ANDP700>3.0.CO;2-K).
The article is part of: P. Mittelstaedt, G. Nimtz (Guest Eds.):
Proceedings of the Workshop Superluminal(?) Velocities: Tunneling Time,
Barrier Penetration, Non-Trivial Vacua, Philosophy of Physics,
June 1998, Cologne.
Annalen der Physik (Leipzig), 8. Series, **7**:7-8(1998)593-782.
[SPIRES record]

**Abstract**:
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.

- Electronic copy of the article: Annalen der Physik (Leipzig)
- Electronic copy of the preprint version: hep-th/9810221
- Citations
- Misprints, errata, addenda:

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