Quantum Field Theory Under the Influence of External Conditions (QFEXT07)
M Bordag and V M Mostepanenko
2008 J. Phys. A: Math. Theor. 41 160301
Abstract: (http://www.iop.org/EJ/abstract/-alert=29097/1751-8121/41/16/160301)
This special issue contains papers reflecting talks
presented at the 8th Workshop on Quantum Field Theory Under the
Influence of External Conditions (QFEXT07), held on 17–21 September
2007, at Leipzig University. This workshop gathered 108 physicists and
mathematicians working on problems which are focused on the following
topics:
•Casimir and van der Waals forces—progress in theory and new experiments, applications at micro- and nano-scale
•Casimir effect—exact results, approximate methods and mathematical problems
•Vacuum quantum effects in classical background
fields—renormalization issues, singular backgrounds, applications to
particle and high energy physics
•Vacuum energy and gravity, vacuum energy in supersymmetric and noncommutative theories.
This workshop is part of a series started in 1989
and 1992 in Leipzig by Dieter Robaschik, and continued in 1995, 1998
and 2001 in Leipzig by Michael Bordag. In 2003 this Workshop was
organized by Kimball A Milton in Oklahoma, in 2005 by Emilio Elizalde
in Barcelona and in 2007 it returned to Leipzig.
The field of physics after which this series of
workshops is named is remarkably broad. It stretches from experimental
work on the measurement of dispersion forces between macroscopic bodies
to quantum corrections in the presence of classical background fields.
The underlying physical idea is that even in its ground state (vacuum)
a quantum system responds to changes in its environment. The
universality of this idea makes the field of its application so very
broad. The most prominent manifestation of vacuum energy is the Casimir
effect. This is, in its original formulation, the attraction between
conducting planes due to the vacuum fluctuations of the electromagnetic
field. In a sense, this is the long-range tail of the more general
dispersion forces acting between macroscopic bodies. With the progress
in nanotechnology, dispersion forces become of direct practical
significance. On a more theoretical side, the vacuum energy manifests
itself as quantum corrections to masses of classical background fields
like solitons. In astrophysics and cosmology it is discussed as a
possible source for dark energy. The growing interest in this field can
be judged from the number of citations received each year by the
original paper by Casimir. This is shown in figure 1 (below).
Although such numbers must be viewed with caution,
the increase of citations over the past decade is impressive. The most
significant progress in the field during the last few years was made in
the following three directions: precision measurements of the Casimir
and Casimir–Polder force, applications of the Lifshitz theory to real
materials, and calculation of dispersion interactions between
arbitrarily shaped bodies. With regard to measurements, modern
laboratory techniques, such as atomic force microscopes and
micromachined oscillators, allow one to obtain experimental data with
an error of about a fraction of one percent. The comparison of the
experimental data obtained at room temperature with the Lifshitz theory
revealed serious problems and gave rise to controversial approaches.
Some of these approaches were found to be consistent with data within
an accuracy of 1–2%, whereas some others were found to be excluded by
the data at a high confidence level. In the calculation of dispersion
interactions
Figure 1. The number of citations received each year by the original paper by Casimir.
between arbitrarily shaped bodies important progress
has been made using the representation of the interaction energy in
terms of functional determinants or in the equivalent T-matrix
approach. These representations allow for a direct numerical
computation of the forces for ideal metal and dielectric configurations
at any fixed separation. The analytical asymptotic expansions at both
large and short separations can also be obtained. The latter, for the
first time, demonstrated an analytic correction beyond the proximity
force approximation. This has put the comparison of experiment with
theory on a solid foundation.
We have divided the talks presented at the workshop into seven
sections. Section I reflects theoretical progress achieved for
arbitrarily shaped bodies. Section II is devoted to problems which
arise in the Lifshitz theory in application to real materials. Sections
III and IV cover the experimental issues and particle–surface
interactions including their role in nanostructures. Sections V and VI
contain papers on more traditional subjects like quantum effects in
background fields and gravitational implications. Section VII covers
the role of quantum effects in black holes, cosmology and some
questions of a more mathematical character.
As any rapidly developing field, quantum field theory under the
influence of external conditions gives rise to numerous hot
discussions. These discussions took place at the meeting and they are
reflected in many contributions to this issue. The Guest Editors have
not tried to smooth sharp contradictions between speakers but tried to
ensure a fair treatment of all contributions.
The referees performed a very important role,
helping to improve the presentation significantly in many contributions
and to make them more clear for the reader. Our special gratitude goes
to the staff of Journal of Physics A: Mathematical and Theoretical whose expertise and patience allowed us to successfully solve all problems arising in the publication process.
The organizers of the workshop are grateful to the University of
Leipzig for providing an excellent environment, especially to the
secretaries of the Institute for Theoretical Physics for their support
in administrative tasks. Both the organizers and participants are
grateful to the supporting organizations, namely the Deutsche
Forschungsgemeinschaft (DFG) (GZ: BO 1112/15-1 and 4851/295/07) and the
Naturwissenschaftlich-Theoretisches Zentrum (NTZ) of the University of
Leipzig. Thanks to their support it was possible to cover local
expenses and partly cover travel costs, and to waive the conference fee
for many participants.
M Bordag and V M Mostepanenko
Guest Editors
----------------------------- Interesting papers:
How does Casimir energy fall? III. Inertial forces on vacuum energy
K V Shajesh, Kimball A Milton, Prachi Parashar and Jeffrey A Wagner
2008 J. Phys. A: Math. Theor. 41 164058 (9pp)
Abstract
Vacuum stress-energy density and its gravitational implications
Ricardo Estrada, Stephen A Fulling, Lev Kaplan, Klaus Kirsten, Zhonghai Liu and Kimball A Milton
2008 J. Phys. A: Math. Theor. 41 164055 (11pp)
Abstract
Gravitational and inertial mass of Casimir energy
Kimball A Milton, Stephen A Fulling, Prachi Parashar, August Romeo, K V Shajesh and Jeffrey A Wagner
2008 J. Phys. A: Math. Theor. 41 164052 (12pp)
Abstract
Vacuum structure and boundary renormalization group
M Asorey and J M Mun~oz-Castan~eda
2008 J. Phys. A: Math. Theor. 41 164043 (7pp)
Abstract
Surface modes and photonic modes in Casimir calculations for a compact cylinder
V V Nesterenko
2008 J. Phys. A: Math. Theor. 41 164005 (8pp)
Abstract