Electromagnetic Lifshitz formula for small-width mirrors from functional determinants

We extend a recently proposed Quantum Field Theory (QFT) approach to the Lifshitz formula, originally implemented for a real scalar field, to the case of a fluctuating vacuum electromagnetic (EM) field, coupled to two flat, parallel mirrors. The general result is presented in terms of the invariants of the vacuum polarization tensors due to the media on each mirror. We consider mirrors that have small widths, with the zero-width limit as a particular case. We apply the latter to models involving graphene sheets, obtaining results which are consistent with previous ones.Comment: 15 pages, 2 figure

Carbon nanotube sensor for vibrating molecules

The transport properties of a CNT capacitively coupled to a molecule vibrating along one of its librational modes are studied and its transport properties analyzed in the presence of an STM tip. We evaluate the linear charge and thermal conductances of the system and its thermopower. They are dominated by position-dependent Franck-Condon factors, governed by a position-dependent effective coupling constant peaked at the molecule position. Both conductance and thermopower allow to extract some information on the position of the molecule along the CNT. Crucially, however, thermopower sheds also light on the vibrational levelspacing, allowing to obtain a more complete characterization of the molecule even in the linear regime

Quantum dissipative effects in graphene-like mirrors

We study quantum dissipative effects due to the accelerated motion of a single, imperfect, zero-width mirror. It is assumed that the microscopic degrees of freedom on the mirror are confined to it, like in plasma or graphene sheets. Therefore, the mirror is described by a vacuum polarization tensor $\Pi_{\alpha\beta}$ concentrated on a time-dependent surface. Under certain assumptions about the microscopic model for the mirror, we obtain a rather general expression for the Euclidean effective action, a functional of the time-dependent mirror's position, in terms of two invariants that characterize the tensor $\Pi_{\alpha\beta}$. The final result can be written in terms of the TE and TM reflection coefficients of the mirror, with qualitatively different contributions coming from them. We apply that general expression to derive the imaginary part of the `in-out' effective action, which measures dissipative effects induced by the mirror's motion, in different models, in particular for an accelerated graphene sheet.Comment: 8 pages, 2 figures. Minor changes, version to be published in Phys. Rev.

Segunda aproximación al enigma de los Ángeles Arcabuceros

En este trabajo se profundiza en el análisis y observación de estas figuras. A partir de ello abordamos un posible significado de cada uno de los elementos independientes que componen estas representaciones artísticas. El mismo estaría relacionado con la esencia pura de la conquista española: la monarquía, la religión y la fuerza militar, aspectos que confluyen para conformar el Ángel Arcabucero

Del Management al Marketing

Artículo elaborado en base al trabajo presentado por la autora para el posgrado de Dirección y administración estratégica del Sistema de Educación a Distancia de la Universidad Católica de Salta. 2008

Vacuum fluctuation effects due to an Abelian gauge field in 2 + 1 dimensions, in the presence of moving mirrors

We study the Dynamical Casimir Effect (DCE) due to an Abelian gauge field in 2+1 dimensions, in the presence of semitransparent, zero-width mirrors, which may move or deform in a time-dependent way. We obtain general expressions for the probability of motion-induced pair creation, which we render in a more explicit form, for some relevant states of motion.Fil: Fosco, Cesar Daniel. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Remaggi, María Laura. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Rodríguez, María Cristina. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentin

Towards Micromechanical Sensors with (La,Sr)MnO3 Epitaxial Films☆

Abstract The rich spectrum of functionalities exhibited by oxide thin films is an appealing feature for the development of micro and nanomechanical devices [1,2] . MEMS made of heterostructures of crystalline oxide materials having targeted physical properties may be applied as sensors having different integrated functionalities. In this work, we explore the feasibility of manganite thin film based epitaxial MEMS for magnetic micromechanical sensing. We investigate the electromechanical properties of LSMO freestanding structures for future applications in the field of micromechanical magnetic sensors

Object-based reverberation for spatial audio

Object-based audio is gaining momentum as a means for future audio content to be more immersive, interactive, and accessible. Recent standardization developments make recommendations for object formats; however, the capture, production, and reproduction of reverberation is an open issue. In this paper parametric approaches for capturing, representing, editing, and rendering reverberation over a 3D spatial audio system are reviewed. A framework is proposed for a Reverberant Spatial Audio Object (RSAO), which synthesizes reverberation inside an audio object renderer. An implementation example of an object scheme utilizing the RSAO framework is provided, and supported with listening test results, showing that: the approach correctly retains the sense of room size compared to a convolved reference; editing RSAO parameters can alter the perceived room size and source distance; and, format-agnostic rendering can be exploited to alter listener envelopment