Image and Coherence Transfer in the Stimulated Down-conversion Process

The intensity transverse profile of the light produced in the process of stimulated down-conversion is derived. A quantum-mechanical treatment is used. We show that the angular spectrum of the pump laser can be transferred to the stimulated down-converted beam, so that images can also be transferred from the pump to the down-converted beam. We also show that the transfer can occur from the stimulating beam to the down-converted one. Finally, we study the process of diffraction through an arbitrarily shaped screen. For the special case of a double-slit, the interference pattern is explicitly obtained. The visibility for the spontaneous emitted light is in accordance with the van Cittert - Zernike theorem for incoherent light, while the visibility for the stimulated emitted light is unity. The overall visibility is in accordance with previous experimental results

Control of conditional pattern with polarization entanglement

Conditional interference patterns can be obtained with twin photons from spontaneous parametric down-conversion and the phase of the pattern can be controlled by the relative transverse position of the signal and idler detectors. Using a configuration that produces entangled photons in both polarization and transverse momentum we report on the control of the conditional patterns by acting on the polarization degree of freedom.Comment: Submitted for publication in Optics Communication

El Teatro español sobre apropiación de menores. La puesta en escena como espacio de identidad y memoria

A más de diez años de las investigaciones de Ricard Vinyes sobre los niños perdidos del franquismo es posible establecer un panorama sobre la repercusión del tema en la narrativa y el teatro español. Si bien la presencia del discurso historiográfico persiste en el tratamiento de los dos géneros, la dramaturgia supera la base fáctica introduciendo personajes más oníricos y espectrales. Tal es el caso de las obras Si un día me olvidara de Raúl Hernández Garrido y Los niños perdidos de Laila Ripoll. A modo de introducción se retomará el antecedente argentino, ya que este ha servido de modelo tanto para las investigaciones sobre el robo de menores en España como para la construcción de los personajes llevados a escena.More than ten years after Ricard Vinyes' research on lost children during Francoism, it is possible to set up a picture of the impact of this subject in Spanish narrative and theater. While the presence of the historiographical discourse persists in the treatment of both genres, drama overcomes the factual basis by introducing more dreamlike and spectral characters. Such is the case of Raúl Hernández Garrido's Si un día me olvidaras and Los niños perdidos by Laila Ripoll. The Argentinian precedent will frame this discussion, since it has been used as a reference not only for historical research but also for the literary representation of the issue of stolen children during Franco's dictatorship in Spain

Dressed tunneling approximation for electronic transport through molecular transistors

A theoretical approach for the non-equilibrium transport properties of nanoscale systems coupled to metallic electrodes with strong electron-phonon interactions is presented. It consists in a resummation of the dominant Feynman diagrams from the perturbative expansion in the coupling to the leads. We show that this scheme eliminates the main pathologies found in previous simple analytical approaches for the polaronic regime. The results for the spectral and transport properties are compared with those from several other approaches for a wide range of parameters. The method can be formulated in a simple way to obtain the full counting statistics. Results for the shot and thermal noise are presented.Comment: 11 pages, 11 figures. Accepted for publication in Physical Review

Spatial correlations in parametric down-conversion

The transverse spatial effects observed in photon pairs produced by parametric down-conversion provide a robust and fertile testing ground for studies of quantum mechanics, non-classical states of light, correlated imaging and quantum information. Over the last 20 years there has been much progress in this area, ranging from technical advances and applications such as quantum imaging to investigations of fundamental aspects of quantum physics such as complementarity relations, Bell's inequality violation and entanglement. The field has grown immensely: a quick search shows that there are hundreds of papers published in this field. The objective of this article is to review the building blocks and major theoretical and experimental advances in the field, along with some possible technical applications and connections to other research areas.Comment: 116 pages, 35 figures. To appear in Physics Report

Experimental determination of multipartite entanglement with incomplete information

Multipartite entanglement is very poorly understood despite all the theoretical and experimental advances of the last decades. Preparation, manipulation and identification of this resource is crucial for both practical and fundamental reasons. However, the difficulty in the practical manipulation and the complexity of the data generated by measurements on these systems increase rapidly with the number of parties. Therefore, we would like to experimentally address the problem of how much information about multipartite entanglement we can access with incomplete measurements. In particular, it was shown that some types of pure multipartite entangled states can be witnessed without measuring the correlations [M. Walter et al., Science 340, 1205 (2013)] between parties, which is strongly demanding experimentally. We explore this method using an optical setup that permits the preparation and the complete tomographic reconstruction of many inequivalent classes of three- and four-partite entangled states, and compare complete versus incomplete information. We show that the method is useful in practice, even for non-pure states or non ideal measurement conditions.Comment: 12 pages, 7 figures. Close to published versio

What do resident physicians know about nutrition? A survey at a university hospital

info:eu-repo/semantics/publishedVersio