921 research outputs found
Polarization entangled state measurement on a chip
The emerging strategy to overcome the limitations of bulk quantum optics
consists of taking advantage of the robustness and compactness achievable by
the integrated waveguide technology. Here we report the realization of a
directional coupler, fabricated by femtosecond laser waveguide writing, acting
as an integrated beam splitter able to support polarization encoded qubits.
This maskless and single step technique allows to realize circular transverse
waveguide profiles able to support the propagation of Gaussian modes with any
polarization state. Using this device, we demonstrate the quantum interference
with polarization entangled states and singlet state projection.Comment: Revtex, 5+2 pages (with supplementary information), 4+1 figure
A path integral for classical dynamics, entanglement, and Jaynes-Cummings model at the quantum-classical divide
The Liouville equation differs from the von Neumann equation 'only' by a
characteristic superoperator. We demonstrate this for Hamiltonian dynamics, in
general, and for the Jaynes-Cummings model, in particular. -- Employing
superspace (instead of Hilbert space), we describe time evolution of density
matrices in terms of path integrals which are formally identical for quantum
and classical mechanics. They only differ by the interaction contributing to
the action. This allows to import tools developed for Feynman path integrals,
in order to deal with superoperators instead of quantum mechanical commutators
in real time evolution. Perturbation theory is derived. Besides applications in
classical statistical physics, the "classical path integral" and the parallel
study of classical and quantum evolution indicate new aspects of (dynamically
assisted) entanglement (generation). Our findings suggest to distinguish
'intra'- from 'inter-space' entanglement.Comment: 22 pages; based on invited talk at Quantum 2010 - Advances in
Foundations of Quantum mechanics and Quantum Information with Atoms and
Photons (Torino, May 2010). To appear in Int. J. Qu. Inf
AFLATOXIN B1 IN CORN: DIRECT VERIFICATION OF CONTAMINATION THROUGH AN AUTOMATIC COMPUTERIZED SYSTEM BASED ON THE FLUORESCENCE
"Aflaflesh" is a computer based instrument, designed combining a visual data acquisition system with a sophisticated software of acquisition and analysis of images. This system allows you to check on a representative sample (5/10 kg) contamination of corn by AFB1, using fluorescence under UV light when the grain is contaminated. To optimize the use of this control equipment were analyzed in two phases, a total of 80 samples comparing the results obtained by chemical analysis (Hplc) to those obtained using "Aflaflesh". Initially the study was set to correlate the number of contaminated grains to the ppb read by the official method, Hplc; the second step was to correlate ppb values to the number of pixel of contaminated surface of the grains read by the "Aflaflesh" instrument. The apparatus was then calibrated through a statistical analysis of the results obtained, to allow a direct reading of the AFB1 concentrations in a short period of time (15 min) without the assistance of specialized personnel
Engineering a C-Phase quantum gate: optical design and experimental realization
A two qubit quantum gate, namely the C-Phase, has been realized by exploiting
the longitudinal momentum (i.e. the optical path) degree of freedom of a single
photon. The experimental setup used to engineer this quantum gate represents an
advanced version of the high stability closed-loop interferometric setup
adopted to generate and characterize 2-photon 4-qubit Phased Dicke states. Some
experimental results, dealing with the characterization of multipartite
entanglement of the Phased Dicke states are also discussed in detail.Comment: accepted for publication on EPJ
General linear dynamics - quantum, classical or hybrid
We describe our recent proposal of a path integral formulation of classical
Hamiltonian dynamics. Which leads us here to a new attempt at hybrid dynamics,
which concerns the direct coupling of classical and quantum mechanical degrees
of freedom. This is of practical as well as of foundational interest and no
fully satisfactory solution of this problem has been established to date.
Related aspects will be observed in a general linear ensemble theory, which
comprises classical and quantum dynamics in the form of Liouville and von
Neumann equations, respectively, as special cases. Considering the simplest
object characterized by a two-dimensional state-space, we illustrate how
quantum mechanics is special in several respects among possible linear
generalizations.Comment: 17 pages; based on invited talks at the conferences DICE2010
(Castiglioncello, Italia, Sept 13-17, 2010) and Quantum Field Theory and
Gravity (Regensburg, Germany, Sept 28 - Oct 1, 2010
Bell scenarios in which nonlocality and entanglement are inversely related
We show that for two-qubit chained Bell inequalities with an arbitrary number
of measurement settings, nonlocality and entanglement are not only different
properties but are inversely related. Specifically, we analytically prove that
in absence of noise, robustness of nonlocality, defined as the maximum fraction
of detection events that can be lost such that the remaining ones still do not
admit a local model, and concurrence are inversely related for any chained Bell
inequality with an arbitrary number of settings. The closer quantum states are
to product states, the harder it is to reproduce quantum correlations with
local models. We also show that, in presence of noise, nonlocality and
entanglement are simultaneously maximized only when the noise level is equal to
the maximum level tolerated by the inequality; in any other case, a more
nonlocal state is always obtained by reducing the entanglement. In addition, we
observed that robustness of nonlocality and concurrence are also inversely
related for the Bell scenarios defined by the tight two-qubit three-setting
inequality, and the tight two-qutrit inequality .Comment: 9 page
Evaluation of antifungal effect of gaseous ozone in a meat processing plant
Ozone is already known as effective food/environmental disinfection agent, thanks to its oxidative action towards microbial cell components. Bactericidal effect of ozone is well documented, while data concerning its inhibitory activity towards fungi are still ambiguous. Our study aims to evaluate the antimicrobial activity of gaseous ozone towards potentially contaminant fungi in a meat production plant in real working conditions. M2 and M5S5 plates were inoculated with
Aspergillus niger, Penicillium roqueforti, Mucor racemosus, Saccharomyces cerevisiae
strains and positioned in a deboning room, where gaseous ozone was dispensed throughout
the night (until a maximum concentration of 20 ppm). Nine different points were chosen,
based on height and distance from the ozone dispenser. After the treatment, the presence of
strains growth was evaluated. Gaseous ozone did not show any inhibitory activity against
mould strains, as optimum growth during all the trials was observed. An appreciable and
constant microbicidal effect against S. cerevisiae was evidenced, with a mean value of 2.8 Log
reduction. Our results suggest the importance of the definition of environmental and technical
use conditions in order to optimise the antimicrobial efficacy of ozone in real working
situations in food industries
Thyroid ultrasonography reporting: consensus of Italian Thyroid Association (AIT), Italian Society of Endocrinology (SIE), Italian Society of Ultrasonography in Medicine and Biology (SIUMB) and Ultrasound Chapter of Italian Society of Medical Radiology (SIRM)
Thyroid ultrasonography (US) is the gold standard for thyroid imaging and its widespread use is due to an optimal spatial resolution for superficial anatomic structures, a low cost and the lack of health risks. Thyroid US is a pivotal tool for the diagnosis and follow-up of autoimmune thyroid diseases, for assessing nodule size and echostructure and defining the risk of malignancy in thyroid nodules. The main limitation of US is the poor reproducibility, due to the variable experience of the operators and the different performance and settings of the equipments. Aim of this consensus statement is to standardize the report of thyroid US through the definition of common minimum requirements and a correct terminology. US patterns of autoimmune thyroid diseases are defined. US signs of malignancy in thyroid nodules are classified and scored in each nodule. We also propose a simplified nodule risk stratification, based on the predictive value of each US sign, classified and scored according to the strength of association with malignancy, but also to the estimated reproducibility among different operators
antifungal activity of rosemary essential oil against foodstuffs fungi
The essential oils are well known for their antibacteric, antomycotic and insecticide effects. In this research the antomycotic activity of Rosemary essential oil has been tested in vitro versus different moulds, common contaminants of food and feed, as Aspergillus flavus, Aspergillus ochraceus, Aspergillus niger, Aspergillus ustus, Penicillium expansum, Penicillium aurantio-griseum, Fusarium moniliforme. The Rosemary essential oil tested (produced in Sardegna, Italy) shows a different efficacy against various moulds and his activity seems to be produced by borneol, α-pinene, eucalyptol, camphor and limonene. Aspergillus and Penicillium are the genus showing an important inhibition of their development in vitro. Rosemary essential oil for these natural properties can be used as antimycotic additive to extended shelf-life of many foodstuffs
Investigación sobre un pasteurizador de túnel para las aceitunas de mesa “Nocellara del Belice” procesadas mediante el “Método Castelvetrano”
The influence of pasteurization temperature and time of treatment on the flesh firmness and the evolution of microbial communities was studied for table olives Cv. Nocellara del Belice, packed in glass jars and processed with a tunnel pasteurizer. The experiment was first carried out on the laboratory level in order to select the optimal combination of pasteurization time/temperature so as to obtain the proper balance between the consistency of the pulp and the microbiological quality of the final product. Pasteurization at industrial scale was then carried out in a tunnel pasteurizer applying the treatment at 75 °C for 8 min in the thermal center of the jars. Besides flesh firmness and microbial evolutions, the pH, total titratable acidity (TTA) and color were evaluated for the table olives during storage at 6, 12 and 15 months from packing. The table olives showed a high stability and acceptable flesh firmness for the entire period under observation. Specifically, olive pulp texture decreased during the storage period, but the softening was most evident in the deeper layers of the pulp. The results indicated that the storage period should not exceed 6 months. Although the hygiene is preserved, after this period the firmness might not be acceptable to consumers.En el presente trabajo se estudió la influencia de la temperatura y del tiempo de pasteurización en la firmeza de la pulpa y la evolución de las comunidades microbianas para la aceituna de mesa “Nocellara del Belice” procesadas con un pasteurizador de túnel. El experimento se llevó a cabo preliminarmente a nivel de laboratorio con el fin de seleccionar la combinación óptima de tiempo/temperatura de pasteurización para obtener el compromiso adecuado entre la consistencia de la pulpa y la calidad microbiológica del producto final. A continuación se llevó a cabo la pasteurización en escala industrial dentro de un pasteurizador de túnel aplicando el tratamiento a 75 ° C durante 8 minutos. Fueron evaluados pH, acidez total titulable (ATT) y el color para las aceitunas de mesa durante el almacenamiento a los 6, 12 y 15 meses de envasado. Las aceitunas de mesa mostraron una alta estabilidad y una firmeza de pulpa aceptable para todo el período de observación; en particular, la textura de pulpa disminuyó durante el período de almacenamiento, pero el ablandamiento fue más evidente en las capas más profundas de la pulpa. Los resultados indicaron que el período de almacenamiento no debe ser superior a 6 meses
- …