4,402 research outputs found

    Subspace code constructions

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    We improve on the lower bound of the maximum number of planes of PG(8,q){\rm PG}(8,q) mutually intersecting in at most one point leading to the following lower bound: Aq(9,4;3)q12+2q8+2q7+q6+q5+q4+1{\cal A}_q(9, 4; 3) \ge q^{12}+2q^8+2q^7+q^6+q^5+q^4+1 for constant dimension subspace codes. We also construct two new non-equivalent (6,(q31)(q2+q+1),4;3)q(6, (q^3-1)(q^2+q+1), 4; 3)_q constant dimension subspace orbit-codes

    Los usos políticos de la comedia. Una interpretación de la Mandrágora

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    Effects of a uniform acceleration on atom-field interactions

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    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

    Local Bridge Inspections

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    We will discuss local bridge inspection requirements, how to make your program successful, and federal requirements that locals need to be aware of

    Spiral pattern: universe, normal heart, and complex congenital defects

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    Non-thermal effects of acceleration in the resonance interaction between two uniformly accelerated atoms

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    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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