Entanglement Percolation with Bipartite Mixed States

We develop a concept of entanglement percolation for long-distance singlet generation in quantum networks with neighboring nodes connected by partially entangled bipartite mixed states. We give a necessary and sufficient condition on the class of mixed network states for the generation of singlets. States beyond this class are insufficient for entanglement percolation. We find that neighboring nodes are required to be connected by multiple partially entangled states and devise a rich variety of distillation protocols for the conversion of these states into singlets. These distillation protocols are suitable for a variety of network geometries and have a sufficiently high success probability even for significantly impure states. In addition to this, we discuss possible further improvements achievable by using quantum strategies including generalized forms of entanglement swapping.Comment: 6+ pages, 5 figures; Published versio

The Einstein-Podolsky-Rosen paradox: from concepts to applications

This Colloquium examines the field of the EPR Gedankenexperiment, from the original paper of Einstein, Podolsky and Rosen, through to modern theoretical proposals of how to realize both the continuous-variable and discrete versions of the EPR paradox. We analyze the relationship with entanglement and Bell's theorem, and summarize the progress to date towards experimental confirmation of the EPR paradox, with a detailed treatment of the continuous-variable paradox in laser-based experiments. Practical techniques covered include continuous-wave parametric amplifier and optical fibre quantum soliton experiments. We discuss current proposals for extending EPR experiments to massive-particle systems, including spin-squeezing, atomic position entangle- ment, and quadrature entanglement in ultra-cold atoms. Finally, we examine applications of this technology to quantum key distribution, quantum teleportation and entanglement-swapping.Comment: Colloquium in press in Reviews of Modern Physics, accepted Dec 200

Onsager Loop-Transition and First Order Flux-Line Lattice Melting in High-TcT_c Superconductors

Monte-Carlo simulations in conjunction with finite-size scaling analysis are used to investigate the $(H,T)$-phase diagram in uniaxial anisotropic high- $T_c$ superconductors, both in zero magnetic field and in intermediate magnetic fields for various mass-anisotropies. The model we consider is the uniformly frustrated anisotropic Villain Model. In zero magnetic field, and for all anisotropies considered, we find one single second order phase transition, mediated by an Onsager vortex-loop blowout. This is the superconductor-normal metal transition.A comparison with numerical simulations and a critical scaling analysis of the zero-field loop-transition yields the same exponent of the loop distribution function at the critical point. In the intermediate magnetic field regime, we find two anomalies in the specific heat. The first anomaly at a temperature $T_m$ is associated with the melting transition of the flux-line lattice. The second anomaly at a temperature $T_z$ is one where phase coherence along the field direction is destroyed. We argue that $T_m=T_z$ in the thermodynamic and continuum limit. Hence, there is no regime where the flux line lattice melts into a disentangled flux-line liquid. The loss of phase coherence parallel to the magnetic field in the sample is argued to be due to the proliferation of closed non-field induced vortex loops on the scale of the magnetic length in the problem, resulting in flux-line cutting and recombination. In the flux-line liquid phase, therefore, flux-lines appear no longer to be well defined entities. A finite-size scaling analysis of the delta function peak specific heat anomaly at the melting transition is used to extract the discontinuity of the entropy at the melting transition.This entropy discontinuity is found to increase rapidly with mass-anisotropy.Comment: 22 pages, 11 figures included, to be published in Phys. Rev. B, 57 xxx (1998

Frozen and Invariant Quantum Discord under Local Dephasing Noise

In this chapter, we intend to explore and review some remarkable dynamical properties of quantum discord under various different open quantum system models. Specifically, our discussion will include several concepts connected to the phenomena of time invariant and frozen quantum discord. Furthermore, we will elaborate on the relation of these two phenomena to the non-Markovian features of the open system dynamics and to the usage of dynamical decoupling protocols.Comment: 29 pages, 8 figure

The sudden change phenomenon of quantum discord

Even if the parameters determining a system's state are varied smoothly, the behavior of quantum correlations alike to quantum discord, and of its classical counterparts, can be very peculiar, with the appearance of non-analyticities in its rate of change. Here we review this sudden change phenomenon (SCP) discussing some important points related to it: Its uncovering, interpretations, and experimental verifications, its use in the context of the emergence of the pointer basis in a quantum measurement process, its appearance and universality under Markovian and non-Markovian dynamics, its theoretical and experimental investigation in some other physical scenarios, and the related phenomenon of double sudden change of trace distance discord. Several open questions are identified, and we envisage that in answering them we will gain significant further insight about the relation between the SCP and the symmetry-geometric aspects of the quantum state space.Comment: Lectures on General Quantum Correlations and their Applications, F. F. Fanchini, D. O. Soares Pinto, and G. Adesso (Eds.), Springer (2017), pp 309-33

ANÁLISE EXPLORATÓRIA DOS POTENCIAIS EFEITOS DAS MUDANÇAS CLIMÁTICAS NOS "VALES DA UVA GOETHE"

The future of agriculture has been conditioned by uncertainties about the effects of climate change. Thus, the main goal of this work is to develop an exploratory analysis of the potential impacts of climate change in dynamics in the vitiviniculture in the region bounded by the Indication of Origin of Vales da Uva Goethe. The analysis was developed based on direct consultation at producers and production and climate data. The results indicate that only share of producers has related changes in the quantity and quality of the grapes to the effects of climate change. However, there was an actual change in climate. The average monthly minimum temperatures increased from 5.75°C to 8.30°C 1924-2012, which can increase the probability of occurrence of disease and pests associated with high average temperatures.O futuro da agricultura está condicionado as incertezas envolvidas em relação aos efeitos das mudanças climáticas. Deste modo, o objetivo principal deste trabalho é desenvolver uma análise exploratória a respeito dos potenciais impactos decorrentes da mudança na dinâmica climática na vitivinicultura na região delimitada pela Indicação de Procedência dos Vales da Uva Goethe. A análise foi desenvolvida com base em consulta direta aos produtores e dados climáticos e da produção da região. Os resultados indicam que apenas parcela dos produtores relaciona as variações na quantidade e na qualidade das uvas aos efeitos das mudanças climáticas. Todavia, constatou-se uma efetiva alteração no clima. As temperaturas médias mínimas mensais aumentaram de 5,75° C para 8,30° C entre 1924 a 2012, o que pode elevar a probabilidade de ocorrência de doenças e pragas associadas às altas temperaturas médias.El futuro de la agricultura está condicionado las incertidumbres sobre los efectos del cambio climático. Por lo tanto, el objetivo principal de este trabajo es desarrollar un análisis exploratorio de los impactos potenciales del cambio climático en la dinámica de la viticultura en la región limitada por la Indicación del Origen de Vales da Uva Goethe. El análisis se desarrolló con base en la consulta directa con los productores y de los datos de la producción y climáticos. Los resultados indican que sólo una parte de los productores en relación con los cambios en la cantidad y calidad de la uva a los efectos del cambio climático. Sin embargo, hubo un cambio real en el clima. Las temperaturas mínimas promedio mensual aumentó de 5,75°C para 8,30°C entre 1924-2012, lo que puede aumentar la probabilidad de ocurrencia de enfermedades y plagas asociado con altas temperaturas medias

The High-Acceptance Dielectron Spectrometer HADES

HADES is a versatile magnetic spectrometer aimed at studying dielectron production in pion, proton and heavy-ion induced collisions. Its main features include a ring imaging gas Cherenkov detector for electron-hadron discrimination, a tracking system consisting of a set of 6 superconducting coils producing a toroidal field and drift chambers and a multiplicity and electron trigger array for additional electron-hadron discrimination and event characterization. A two-stage trigger system enhances events containing electrons. The physics program is focused on the investigation of hadron properties in nuclei and in the hot and dense hadronic matter. The detector system is characterized by an 85% azimuthal coverage over a polar angle interval from 18 to 85 degree, a single electron efficiency of 50% and a vector meson mass resolution of 2.5%. Identification of pions, kaons and protons is achieved combining time-of-flight and energy loss measurements over a large momentum range. This paper describes the main features and the performance of the detector system

Estruturação da vigilância epidemiológica e manejo populacional de suídeos asselvajados (Sus scrofa) para área livre de peste suína clássica do Brasil.

Suplemento 2, ref. 30. Edição dos Resumos do 3 Encontro Nacional de Defesa Sanitária Animal, Foz de Iguaçu, dez. 2013

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal