4,098 research outputs found

    Enhanced dynamical entanglement transfer with multiple qubits

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    We present two strategies to enhance the dynamical entanglement transfer from continuous variable (CV) to finite dimensional systems by employing multiple qubits. First, we consider the entanglement transfer to a composite finite dimensional system of many qubits simultaneously interacting with a bipartite CV field. We show that, considering realistic conditions in the generation of CV entanglement, a small number of qubits resonantly coupled to the CV system is sufficient for an almost complete dynamical transfer of the entanglement. Our analysis also sheds further light on the transition between microscopic and macroscopic behaviours of composite finite dimensional systems coupled to bosonic fields (like atomic clouds interacting with light). Furthermore, we present a protocol based on sequential interactions of the CV system with some ancillary qubit systems and on subsequent measurements, allowing to probabilistically convert CV entanglement into `almost perfect' Bell pairs of two qubits. Our proposals are suited for realizations in various experimental settings, ranging from cavity-QED to cavity-integrated superconducting devices.Comment: 10 pages, 8 figures, RevTeX4; terminology revised; accepted for publicatio

    Somatostatin receptor scintigraphy of malignant lymphoma--current status.

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    Somatostatin receptors have been demonstrated on normal as well as activated human lymphocytes in the circulation and within the reticuloendothelial system such as Peyer's patches and the spleen [1]. Also, lymphocyte function such as proliferation and immunoglobulin synthesis has been showed to be affected by somatostatin [2]. Following the demonstration of the presence of high-density somatostatin receptors in a variety of neuroendocrine derived tumors [3], Reubi et al. subsequently reported visualizing non-Hodgkins lymphoma in four patients imaged with Indium-I1l-[DTPA-D-Phel]-Octreotide, an analogue of somatostatin [4]. Autoradiography utilizing 125I-[Tyr3]-Octreotide was used to demonstrate the diffuse distribution of somatostatin receptors in tissue samples of biopsies taken of the involved sites.They suggested that somatostatin receptors could be used as valuable pathobiochemical tissue markers and potentially useful as an in vivo diagnostic tool for human malignant lymphomas. In ten patients studied with malignant lymphoma (Hodgkins disease and non-Hodgkins lymphomas), lymphoma deposits could be demonstrated [5]. In four patients, additional tumor localizations were observed as compared to the results of combined physical and radiological (CT and ultrasound

    Ultimate squeezing through coherent quantum feedback

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    Coherent feedback is the use of feedback loops not involving any measurements for the purpose of quantum control. This can be contrasted to measurement-based feedback where the feedback signal is directed by the result of measurements upon the system. Here, we develop a general framework to describe interferometric coherent feedback loops and prove that, under any such scheme, the steady-state squeezing of a bosonic mode subject to a rotating wave coupling with a white-noise environment and to any quadratic Hamiltonian must abide by a noise-dependent bound that reduces to the 3-dB limit at zero temperature. Such a finding is compared, at fixed dynamical parameters, with the performance of homodyne continuous monitoring of the output modes, which allows one to beat coherent feedback and the 3-dB limit under certain dynamical conditions

    Polymer, metal and ceramic matrix composites for advanced aircraft engine applications

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    Advanced aircraft engine research within NASA Lewis is being focused on propulsion systems for subsonic, supersonic, and hypersonic aircraft. Each of these flight regimes requires different types of engines, but all require advanced materials to meet their goals of performance, thrust-to-weight ratio, and fuel efficiency. The high strength/weight and stiffness/weight properties of resin, metal, and ceramic matrix composites will play an increasingly key role in meeting these performance requirements. At NASA Lewis, research is ongoing to apply graphite/polyimide composites to engine components and to develop polymer matrices with higher operating temperature capabilities. Metal matrix composites, using magnesium, aluminum, titanium, and superalloy matrices, are being developed for application to static and rotating engine components, as well as for space applications, over a broad temperature range. Ceramic matrix composites are also being examined to increase the toughness and reliability of ceramics for application to high-temperature engine structures and components

    Electron beam transfer line design for plasma driven Free Electron Lasers

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    Plasma driven particle accelerators represent the future of compact accelerating machines and Free Electron Lasers are going to benefit from these new technologies. One of the main issue of this new approach to FEL machines is the design of the transfer line needed to match of the electron-beam with the magnetic undulators. Despite the reduction of the chromaticity of plasma beams is one of the main goals, the target of this line is to be effective even in cases of beams with a considerable value of chromaticity. The method here explained is based on the code GIOTTO [1] that works using a homemade genetic algorithm and that is capable of finding optimal matching line layouts directly using a full 3D tracking code.Comment: 9 Pages, 4 Figures. A related poster was presented at EAAC 201

    Differential conditions for constrained nonlinear programming via Pareto optmization

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    We deal with differential conditions for local optimality. The conditions that we derive for inequality constrained problems do not require constraint qualifications and are the broadest conditions based on only first-order and second-order derivatives. A similar result is proved for equality constrained problems, although the necessary conditions require the regularity of the equality constraints

    Tree-level entanglement in quantum electrodynamics

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    We report on a systematic study on the entanglement between helicity degrees of freedom generated at tree level in quantum electrodynamics two-particle scattering processes. We determine the necessary and sufficient dynamical conditions for outgoing particles to be entangled with one another, and expose the hitherto unknown generation of maximal or nearly maximal entanglement through Bhabha and Compton scattering. Our work is an early step in revisiting quantum field theory and high-energy physics in the light of quantum information theory

    Indicatori della lavorazione tessile nel Veneto preromano

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    Among the grave goods of the ancient Veneto burials, ceramic spindle whorls, reels and counterweights are quite common: they are related to the female world, of which the textile manufacturing was an important element. Some years ago, in a paper written for the catalougue of the exhibition Le ore e I giorni delle donne, Verucchio 2007, we started an analysis aimed at recognizing the specific indicators of weaving, such as distaffs, spindles, thread spacers, needles, buttons, along with the recently discovered weaving tablets from Este. The goal of that work was to understand the various levels of specialization involved in the different phases of the production process. We discussed some tool associations that could be considered as “toolkits”, along with some clear diachronic changes in these sets. In this paper we continued this analysis by approaching old and new data from a numerical and ponderal point of view, in order to better understand the specific function of some classes of artifacts, and be able to make hypoteses about the “invisible” tools (wooden spindles, typology and typometry of the looms…). Furthermore, a complete reconstruction of the textiles production process could help us understanding the change (from an individual, domestic activity to a large-scale production) the textile manufacturing underwent during the 1st millennium BC
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