The entangling side of the Unruh-Hawking effect

We show that the Unruh effect can create net quantum entanglement between inertial and accelerated observers depending on the choice of the inertial state. This striking result banishes the extended belief that the Unruh effect can only destroy entanglement and furthermore provides a new and unexpected source for finding experimental evidence of the Unruh and Hawking effects.Comment: 4 pages, 4 figures. Added Journal referenc

Impact of Gamma Radiation on Dynamic RDSON Characteristics in AlGaN/GaN Power HEMTs

GaN high-electron-mobility transistors (HEMTs) are promising next-generation devices in the power electronics field which can coexist with silicon semiconductors, mainly in some radiation-intensive environments, such as power space converters, where high frequencies and voltages are also needed. Its wide band gap (WBG), large breakdown electric field, and thermal stability improve actual silicon performances. However, at the moment, GaN HEMT technology suffers from some reliability issues, one of the more relevant of which is the dynamic on-state resistance (RON_dyn) regarding power switching converter applications. In this study, we focused on the drain-to-source on-resistance (RDSON) characteristics under 60Co gamma radiation of two different commercial power GaN HEMT structures. Different bias conditions were applied to both structures during irradiation and some static measurements, such as threshold voltage and leakage currents, were performed. Additionally, dynamic resistance was measured to obtain practical information about device trapping under radiation during switching mode, and how trapping in the device is affected by gamma radiation. The experimental results showed a high dependence on the HEMT structure and the bias condition applied during irradiation. Specifically, a free current collapse structure showed great stability until 3.7 Mrad(Si), unlike the other structure tested, which showed high degradation of the parameters measured. The changes were demonstrated to be due to trapping effects generated or enhanced by gamma radiation. These new results obtained about RON_dyn will help elucidate trap behaviors in switching transistors

Political allegation and literary speech in "¡Vámonos con Pancho Villa! y Se llevaron el cañón para Bachimba" by Rafael F. Muñoz

El presente artículo muestra el valor literario e ideológico de la narrativa de Rafael F. Muñoz y, más particularmente de sus dos novelas. A lo largo de él se analizan ¡Vámonos con Pancho Villa! y Se llevaron el cañón para Bachimba como ejemplos de obras que responden a las polémicas literarias y políticas de su tiempo sirviéndose de la figura de Pancho Villa.The present article shows the literary and ideological value of the narrative of Rafael F. Muñoz and, more particularly of his two novels. Along him they are analyzed ¡Vámonos con Pancho Villa! and Se llevaron el cañón para Bachimba as examples of works that answer to the literary and political polemics of his time being served Pancho Villa's figure

Mechanical systems subjected to generalized nonholonomic constraints

We study mechanical systems subject to constraint functions that can be dependent at some points and independent at the rest. Such systems are modelled by means of generalized codistributions. We discuss how the constraint force can transmit an impulse to the motion at the points of dependence and derive an explicit formula to obtain the ``post-impact'' momentum in terms of the ``pre-impact'' momentum.Comment: 24 pages, no figure

Physical qubits from charged particles: IR divergences in quantum information

We consider soft photons effects (IR structure of QED) on the construction of physical qubits. Soft-photons appear when we build charged qubits from the asymptotic states of QED. This construction is necessary in order to include the effect of soft photons on entanglement measures. The nonexistence of free charged particles (due to the long range of QED interactions) lead us to question the sense of the very concept of free charged qubit. In this letter, using the "dressing" formalism, we build physical charged qubits from dressed fields which have the correct asymptotic behavior, are gauge invariant, their propagators have a particle pole structure and are free from infrared divergences. Finally, we discuss the impact of the soft corrections on the entanglement measures.Comment: 4 pages, 2 figures, RevTeX. Version 2: Some references update

Global controllability tests for geometric hybrid control systems

Hybrid systems are characterized by having an interaction between continuous dynamics and discrete events. The contribution of this paper is to provide hybrid systems with a novel geometric formulation so that controls can be added. Using this framework we describe some new global controllability tests for hybrid control systems exploiting the geometry and the topology of the set of jump points, where the instantaneous change of dynamics take place. Controllability is understood as the existence of a feasible trajectory for the system joining any two given points. As a result we describe examples where none of the continuous control systems are controllable, but the associated hybrid system is controllable because of the characteristics of the jump set.Comment: 27 pages, 5 figure

Unveiling quantum entanglement degradation near a Schwarzschild black hole

We analyze the entanglement degradation provoked by the Hawking effect in a bipartite system Alice-Rob when Rob is in the proximities of a Schwarzschild black hole while Alice is free falling into it. We will obtain the limit in which the tools imported from the Unruh entanglement degradation phenomenon can be used properly, keeping control on the approximation. As a result, we will be able to determine the degree of entanglement as a function of the distance of Rob to the event horizon, the mass of the black hole, and the frequency of Rob's entangled modes. By means of this analysis we will show that all the interesting phenomena occur in the vicinity of the event horizon and that the presence of event horizons do not effectively degrade the entanglement when Rob is far off the black hole. The universality of the phenomenon is presented: There are not fundamental differences for different masses when working in the natural unit system adapted to each black hole. We also discuss some aspects of the localization of Alice and Rob states. All this study is done without using the single mode approximation.Comment: 16 pages, 10 figures, revtex4. Added Journal referenc

Biorefineries: Achievements and challenges for a bio-based economy

Funding This work was supported by a project (FQM-176) financed by the Junta de Andalucía. FM-M, acknowledges the support from the Global Challenges Research Fund from Swansea University, and from the Royal Society of Chemistry Enablement Grant (E21-7051491439).Climate change, socioeconomical pressures, and new policy and legislation are driving a decarbonization process across industries, with a critical shift from a fossil-based economy toward a biomass-based one. This new paradigm implies not only a gradual phasing out of fossil fuels as a source of energy but also a move away from crude oil as a source of platform chemicals, polymers, drugs, solvents and many other critical materials, and consumer goods that are ubiquitous in our everyday life. If we are to achieve the United Nations’ Sustainable Development Goals, crude oil must be substituted by renewable sources, and in this evolution, biorefineries arise as the critical alternative to traditional refineries for producing fuels, chemical building blocks, and materials out of non-edible biomass and biomass waste. State-of-the-art biorefineries already produce cost-competitive chemicals and materials, but other products remain challenging from the economic point of view, or their scaled-up production processes are still not sufficiently developed. In particular, lignin’s depolymerization is a required milestone for the success of integrated biorefineries, and better catalysts and processes must be improved to prepare bio-based aromatic simple molecules. This review summarizes current challenges in biorefinery systems, while it suggests possible directions and goals for sustainable development in the years to come.Project (FQM-176) financed by the Junta de AndalucíaGlobal Challenges Research Fund from Swansea UniversityRoyal Society of Chemistry Enablement Grant (E21-7051491439

Understanding the impact of line-of-sight in the ergodic spectral efficiency of cellular networks

In this paper we investigate the impact of lineof-sight (LoS) condition in the ergodic spectral efficiency of cellular networks. To achieve this goal, we have considered the kappa-mu shadowed model, which is a general model that provides an excellent fit to a wide set of propagation conditions. To overcome the mathematical complexity of the analysis, we have split the analysis between large and small-scale effects. Building on the proposed framework, we study a number of scenarios that range from heavily-fluctuating LoS to deterministic-LoS. Finally, we shed light on the interplay between fading severity and spectral efficiency by means of the amount of fading.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Complicaciones en el uso de aloinjertos intercalares tras resección de tumores óseos

La reconstrucción ósea mediante aloinjertos intercalares es una técnica de uso frecuente tras resecciones tumorales, que presenta -a largo plazo- mejores resultados que las endoprótesis diafisarias o los autoinjertos vascularizados. Sin embargo, entre las complicaciones más frecuentes destacan las infecciones y las fracturas del aloinjero asociadas a roturas o aflojamientos de la osteosíntesis. Se presentan dos casos tratados con reconstrucciones de este tipo en los que el sistema de osteosíntesis utilizado fracasó, en uno de ellos de forma repetida.The reconstruction of skeletal defects using bone allografts is a frequent procedure after tumoral resections associated to good long-term results, usually better than diaphyseal endoprostheses or autologous grafts. Nevertheless, there are some complications: infection and allograft fracture associated with failure or broken fixation. We report two cases of bone reconstruction in who the fixation failed, twice in one of them