4,522 research outputs found
Subspace code constructions
We improve on the lower bound of the maximum number of planes of mutually intersecting in at most one point leading to the following
lower bound: for
constant dimension subspace codes. We also construct two new non-equivalent
constant dimension subspace orbit-codes
Effects of a uniform acceleration on atom-field interactions
We review some quantum electrodynamical effects related to the uniform
acceleration of atoms in vacuum. After discussing the energy level shifts of a
uniformly accelerated atom in vacuum, we investigate the atom-wall
Casimir-Polder force for accelerated atoms, and the van der
Waals/Casimir-Polder interaction between two accelerated atoms. The possibility
of detecting the Unruh effect through these phenomena is also discussed in
detail.Comment: 6 pages. Special Issue: 20th Central European Workshop on Quantum
Optics - Stockholm - June 201
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Non-thermal effects of acceleration in the resonance interaction between two uniformly accelerated atoms
We study the resonance interaction between two uniformly accelerated
identical atoms, one excited and the other in the ground state, prepared in a
correlated (symmetric or antisymmetric) state and interacting with the scalar
field or the electromagnetic field in the vacuum state. In this case (resonance
interaction), the interatomic interaction is a second-order effect in the
atom-field coupling. We separate the contributions of vacuum fluctuations and
radiation reaction to the resonance energy shift of the system, and show that
only radiation reaction contributes, while Unruh thermal fluctuations do not
affect the resonance interaction. We also find that beyond a characteristic
length scale related to the atomic acceleration, non-thermal effects in the
radiation reaction contribution change the distance-dependence of the resonance
interaction. Finally, we find that previously unidentified features appear,
compared with the scalar field case, when the interaction with the
electromagnetic field is considered, as a consequence of the peculiar nature of
the vacuum quantum noise of the electromagnetic field in a relativistically
accelerated background.Comment: 10 page
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