Manipulating the Coulomb interaction: A Green's function perspective

We present a unified framework for studying Coulomb interactions in arbitrary environments using macroscopic quantum electrodynamics on the basis of the electromagnetic Green's function. Our theory can be used to derive the Coulomb potential of a single charged particle as well as that between two charges in the presence of media, bodies and interfaces of arbitrary shapes. To demonstrate this, we reproduce the well-known screened Coulomb force, account for local-field effects and consider new cases such as a dielectric cavity and a conducting plate with a hole

Diritti Umani e "nuovi diritti": governo della globalizzazione e desocializzazione del diritto

[Resumen] En la actualidad el discurso de los derechos humanos sanciona el fin del viejo principio territorial magnificando la libertad individual. El discurso de los derechos representa el nexo estructural entre la globalización económica y el universalismo jurídico. Y bajo esta perspectiva la globalización materializa la privatización reconducida al parámetro de la lógica utilitaria que marcan las instituciones privadas supraestatales, como el BM, el FMI y el WTO. La estrategia de los “nuevos derechos” manifiesta la ausencia de cualquier forma de mediación del poder político-social a diferencia de lo sucedido con las anteriores generaciones de derechos; los “nuevos derechos” tienden a presentarse fundados sólo en la nuda individualidad biológica. De esta consideración se deriva una evidente paradoja, consistente en que los pretendidos nuevos derechos se transforman de súbito en “dependencias” por estar subordinados a la lógica del mercado y a la burocracia. El análisis de la justificación de los nuevos derechos manifiesta que en biopolítica prevalece la biología de los seres humanos, sin tener en cuenta las necesarias mediaciones que, desde el comienzo de las culturas, autorizan a considerar a los seres humanos como seres también espirituales; es decir, seres necesitados de sentido, comunicación y reciprocidad. Esta situación global puede ser reversible en el marco europeo si se asume una concepción alternativa; otra vía es posible y necesaria para oponerse a lo que hay y avanzar, reafirmando algunas de nuestras tradiciones emancipatorias que exigen la rotunda oposición a las directrices foráneas implícitas en el proyecto de governance, a la propuesta de gobierno burocrático mundial y a la deslocalización del derecho; son dimensiones y riesgos que se ocultan bajo el seudo discurso cosmopolita anglosajón.[Abstract] This article pretends to broach the problematic of the new speech about human rigths in the sphere of economic globalization and the feasible alternatives

Van der Waals interactions between excited atoms in generic environments

We consider the the van der Waals force involving excited atoms in general environments, constituted by magnetodielectric bodies. We develop a dynamical approach studying the dynamics of the atoms and the field, mutually coupled. When only one atom is excited, our dynamical theory suggests that for large distances the van der Waals force acting on the ground-state atom is monotonic, while the force acting in the excited atom is spatially oscillating. We show how this latter force can be related to the known oscillating Casimir--Polder force on an excited atom near a (ground-state) body. Our force also reveals a population-induced dynamics: for times much larger that the atomic lifetime the atoms will decay to their ground-states leading to the van der Waals interaction between ground-state atoms.Comment: 19 pages, 4 figure

High frequency of inadequate test requests for antiphospholipid antibodies in daily clinical practice

Abstract Background: We have empirically noted that many physicians routinely request anti-phospholipid antibodies (aPL) without a correct clinical indication. The aim of this study was to evaluate retrospectively whether aPL testing at our Thrombosis Centre was justified. Methods: Medical records from 520 subjects for aPL screening tests for various clinical conditions were reviewed. The aPL screening tests were: lupus anticoagulant (LA), anti-cardiolipin antibodies (aCL) and anti-β(2) glycoptotein I (aβ(2) GPI). Requests for aPL screening were divided into justified, potentially justified or not adequately justified. Results: aPL testing requests were considered justified in 358 (69%) patients, potentially justified in 66 (12.6%) and not adequately justified in 96 (18.4%). LA was positive in 65 (18%) of justified requests and in only one (1%) of the 96 potentially justified requests. None of the 66 not adequately justified for aPL testing was positive for LA. aβ(2) ..

Dynamical Casimir-Polder interaction between a chiral molecule and a surface

We develop a dynamical approach to study the Casimir-Polder force between a initially bare molecule and a magnetodielectric body at finite temperature. Switching on the interaction between the molecule and the field at a particular time, we study the resulting temporal evolution of the Casimir-Polder interaction. The dynamical self-dressing of the molecule and its population-induced dynamics are accounted for and discussed. In particular, we find that the Casimir-Polder force between a chiral molecule and a perfect mirror oscillates in time with a frequency related to the molecular transition frequency, and converges to the static result for large times.Comment: 10 pages, 4 figure

Tuning the collective decay of two entangled emitters by means of a nearby surface

We consider the radiative properties of a system of two identical correlated atoms interacting with the electromagnetic field in its vacuum state in the presence of a generic dielectric environment. We suppose that the two emitters are prepared in a symmetric or antisymmetric superposition of one ground state and one excited state and we evaluate the transition rate to the collective ground state, showing distinctive cooperative radiative features. Using a macroscopic quantum electrodynamics approach to describe the electromagnetic field, we first obtain an analytical expression for the decay rate of the two entangled two-level atoms in terms of the Green's tensor of the generic external environment. We then investigate the emission process when both atoms are in free space and subsequently when a perfectly reflecting mirror is present, showing how the boundary affects the physical features of the superradiant and subradiant emission by the two coupled emitters. The possibility to control and tailor radiative processes is also discussed.Comment: 11 pages, 8 figure