1,803 research outputs found
Casimir force for cosmological domain walls
We calculate the vacuum fluctuations that may affect the evolution of
cosmological domain walls. Considering domain walls, which are classically
stable and have interaction with a scalar field, we show that explicit symmetry
violation in the interaction may cause quantum bias that can solve the
cosmological domain wall problem.Comment: 15 pages, 2figure
The Zeta Function Method and the Harmonic Oscillator Propagator
We show how the pre-exponential factor of the Feynman propagator for the
harmonic oscillator can be computed by the generalized -function method.
Besides, we establish a direct equivalence between this method and Schwinger's
propertime method.Comment: 12 latex pages, no figure
Casimir Effect in Background of Static Domain Wall
In this paper we investigate the vacuum expectation values of energy-
momentum tensor for conformally coupled scalar field in the standard parallel
plate geometry with Dirichlet boundary conditions and on background of planar
domain wall case. First we calculate the vacuum expectation values of
energy-momentum tensor by using the mode sums, then we show that corresponding
properties can be obtained by using the conformal properties of the problem.
The vacuum expectation values of energy-momentum tensor contains two terms
which come from the boundary conditions and the the gravitational background.
In the Minkovskian limit our results agree with those obtained in [3].Comment: 8 Page
Scalar Casimir Energies of Tetrahedra
New results for scalar Casimir self-energies arising from interior modes are
presented for the three integrable tetrahedral cavities. Since the eigenmodes
are all known, the energies can be directly evaluated by mode summation, with a
point-splitting regulator, which amounts to evaluation of the cylinder kernel.
The correct Weyl divergences, depending on the volume, surface area, and the
corners, are obtained, which is strong evidence that the counting of modes is
correct. Because there is no curvature, the finite part of the quantum energy
may be unambiguously extracted. Dirichlet and Neumann boundary conditions are
considered and systematic behavior of the energy in terms of geometric
invariants is explored.Comment: Talk given at QFEXT 1
Short-range force detection using optically-cooled levitated microspheres
We propose an experiment using optically trapped and cooled dielectric
microspheres for the detection of short-range forces. The center-of-mass motion
of a microsphere trapped in vacuum can experience extremely low dissipation and
quality factors of , leading to yoctonewton force sensitivity.
Trapping the sphere in an optical field enables positioning at less than 1
m from a surface, a regime where exotic new forces may exist. We expect
that the proposed system could advance the search for non-Newtonian gravity
forces via an enhanced sensitivity of over current experiments at
the 1 m length scale. Moreover, our system may be useful for
characterizing other short-range physics such as Casimir forces.Comment: 4 pages, 3 figures, minor changes, Figs. 1 and 2 replace
Thermal diffractive corrections to Casimir energies
We study the interplay of thermal and diffractive effects in Casimir
energies. We consider plates with edges, oriented either parallel or
perpendicular to each other, as well as a single plate with a slit. We compute
the Casimir energy at finite temperature using a formalism in which the
diffractive effects are encoded in a lower dimensional non-local field theory
that lives in the gap between the plates. The formalism allows for a clean
separation between direct or geometric effects and diffractive effects, and
makes an analytic derivation of the temperature dependence of the free energy
possible. At low temperatures, with Dirichlet boundary conditions on the
plates, we find that diffractive effects make a correction to the free energy
which scales as T^6 for perpendicular plates, as T^4 for slits, and as T^4 log
T for parallel plates.Comment: 31 pages, 7 figures, LaTeX. v2: minor typos fixed, version to appear
in PR
Zero-point momentum in Complex media
In this work we apply field regularization techniques to formulate a number
of new phenomena related to momentum induced by electromagnetic zero-point
fluctuations. We discuss the zero-point momentum associated with
magneto-electric media, with moving media, and with magneto-chiral media.Comment: submitted to EPJ
On Casimir Pistons
In this paper we study the Casimir force for a piston configuration in
with one dimension being slightly curved and the other two infinite. We work
for two different cases with this setup. In the first, the piston is "free to
move" along a transverse dimension to the curved one and in the other case the
piston "moves" along the curved one. We find that the Casimir force has
opposite signs in the two cases. We also use a semi-analytic method to study
the Casimir energy and force. In addition we discuss some topics for the
aforementioned piston configuration in and for possible modifications
from extra dimensional manifolds.Comment: 20 pages, To be published in MPL
Non-monotonic thermal Casimir force from geometry-temperature interplay
The geometry dependence of Casimir forces is significantly more pronounced in
the presence of thermal fluctuations due to a generic geometry-temperature
interplay. We show that the thermal force for standard sphere-plate or
cylinder-plate geometries develops a non-monotonic behavior already in the
simple case of a fluctuating Dirichlet scalar. In particular, the attractive
thermal force can increase for increasing distances below a critical
temperature. This anomalous behavior is triggered by a reweighting of relevant
fluctuations on the scale of the thermal wavelength. The essence of the
phenomenon becomes transparent within the worldline picture of the Casimir
effect.Comment: 4 pages, 4 figure
Roughness correction to the Casimir force : Beyond the Proximity Force Approximation
We calculate the roughness correction to the Casimir effect in the parallel
plates geometry for metallic plates described by the plasma model. The
calculation is perturbative in the roughness amplitude with arbitrary values
for the plasma wavelength, the plate separation and the roughness correlation
length. The correction is found to be always larger than the result obtained in
the Proximity Force Approximation.Comment: 7 pages, 3 figures, v2 with minor change
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