Entanglement and correlations in the continuous multi-scale entanglement renormalization ansatz

We investigate the entanglement structure of the continuous multi-scale entanglement renormalization ansatz (cMERA) [Haegeman et al., Phys. Rev. Lett., 110, 100402 (2013)] for ground states of quantum field theories (QFTs). The cMERA, proposed as an extension to QFTs of the lattice MERA, is defined directly in the continuum but is nevertheless naturally equipped with a short-distance scale $1/\Lambda$ that acts as a UV regulator for quantum fluctuations. We consider the simplified setting of Gaussian cMERA for free QFTs, where explicit calculations can be performed. For relativistic free massless bosonic and fermionic QFTs in both 1+1 and 2+1 spacetime dimensions, we show that the cMERA state indeed displays no UV divergences in two-point correlation functions or entanglement entropy, in sharp contrast with the exact ground states.Comment: 28 pages, 20 figures, 4 appendices. Improved with referee's comment

Single-atom control of the optoelectronic response in sub-nanometric cavities

By means of ab-initio time dependent density functional theory calculations carried out on an prototypical hybrid plasmonic device (two metallic nanoparticles bridged by a one-atom junction), we demonstrate the strong interplay between photoinduced excitation of localized surface plasmons and electron transport through the single atom. Such an interplay is remarkably sensitive to the atomic orbitals of the junction. Therefore, we show the possibility of a twofold tuning (plasmonic response and photoinduced current across the juntion) just by changing a single atom in the device.Comment: 5 pages, 5 figure

Stochastic resource allocation with a backhaul constraint for the uplink

We propose a novel stochastic radio resource alloca- tion strategy for the uplink that achieves long-term fairness in terms of similar bitrates considering backhaul and air-interface capacity limitations. We focus on a single cell scenario based on WCDMA technology. We propose to use a maximin criteria to introduce fairness among the different users’ throughputs. An stochastic approximation is implemented to obtain an online algorithm where the Lagrange multipliers are estimated at each scheduling period. Our results show that the proposed scheme achieves higher fairness among the users and, in some cases, a higher sum-rate compared with the well-known proportional fair scheduler.Postprint (author's final draft

Anderson localization in carbon nanotubes: defect density and temperature effects

The role of irradiation induced defects and temperature in the conducting properties of single-walled (10,10) carbon nanotubes has been analyzed by means of a first-principles approach. We find that di-vacancies modify strongly the energy dependence of the differential conductance, reducing also the number of contributing channels from two (ideal) to one. A small number of di-vacancies (5-9) brings up strong Anderson localization effects and a seemly universal curve for the resistance as a function of the number of defects. It is also shown that low temperatures, around 15-65 K, are enough to smooth out the fluctuations of the conductance without destroying the exponential dependence of the resistivity as a function of the tube length.Comment: 4 pages, 4 figure

Molecular epidemiology of Salmonella Typhimurium and Salmonella 4,5,12:i:- isolated from pig farms in Spain

The genetic diversity of 194 salmonella isolates belonging to different phagetypes of S. Typhimurium and S 4,5, 12:i- isolated from both healthy slaughter (157) and diarrhoea-affected (37) pigs was assessed using molecular typing (plasmid profiling and PFGE). The aim of this study was to elucidate the sources of infection, and to follow the spread of specific clones within the infected farms. In spite of the genetic diversity observed amongst the isolates, some clones were more prevalent and widely distributed in the pig population, being detected in several slaughter batches from the same and different farms. This finding suggests the existence of multiple and recurrent infection sources, as well as mechanisms favouring survival, persistence and spreading of certam clones within and between pig farms

How to assist the students while learning from text? Effects of inserting adjunct questions on text processing

This study analyzes the effect of text-inserted questions and post-text-reading questions, i.e., question timing, on students' processing and learning when studying challenging texts. Seventy-six freshmen read two science texts and answered ten adjunct questions with the text available, being tested on learning 5 days afterwards. Questions were presented either after reading the whole text or inserted in the text after reading the relevant information. Online processing data were recorded while reading and searching the texts, and measures of processing strategies (i.e., paraphrases, elaborations) while answering the questions were collected. Compared to students in the post-reading condition, those in the inserted condition spent more time reading the text initially, were more efficient at searching for information in the text, and produced more accurate elaborations, all of which may explain why answering inserted questions in an available text were more efective in terms of learning than answering post-reading questions. Limitations and educational implications of these results are also discussed

Base station on/off strategies for wireless networks powered with energy harvesting sources

In this paper, we present a procedure for switching on and off base stations (BSs) that are powered with solar panels and have finite batteries. In the scenario under consideration it is considered that the BSs are placed at the same site with fully overlapped coverage areas and using different frequencies. We propose a decision strategy where we assume perfect knowledge of the traffic profile and a second approach where a robust Bayesian strategy is considered in order to account for possible error modeling in the traffic profile information.The research leading to these results has received funding from the European Commission in the framework of the FP7 Network of Excellence in Wireless COMmunications NEWCOM# (Grant agreement no. 318306) and project TUCAN3G (Grant agreement no. ICT-2011-601102), from the Spanish Ministry of Economy and Competitiveness (Ministerio de Economía y Competitividad) through the project TEC2011-29006-C03-02 (GRE3N-LINK-MAC), project TEC2013-41315-R (DISNET), and FPI grant BES-2012-052850, and from the Catalan Government (AGAUR) through the grant 2014 SGR 60.Peer ReviewedPostprint (author's final draft