46,428 research outputs found

    Stabilizing Entangled States with Quasi-Local Quantum Dynamical Semigroups

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    We provide a solution to the problem of determining whether a target pure state can be asymptotically prepared using dissipative Markovian dynamics under fixed locality constraints. Beside recovering existing results for a large class of physically relevant entangled states, our approach has the advantage of providing an explicit stabilization test solely based on the input state and constraints of the problem. Connections with the formalism of frustration-free parent Hamiltonians are discussed, as well as control implementations in terms of a switching output-feedback law.Comment: 11 pages, no figure

    Thermal measurements of microwave transmitter feedhorn window

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    Thermal measurements of microwave transmitter feedhorn windows were performed using an imaging infrared radiometer. The measurement technique is described and results are presented for windows made of 0.001-in. Kapton (trademark of Dupont Chemical Co.) and 0.1-in. HTP-6 (Space Shuttle tile material). Measured and calculated temperatures agree well

    Constraints on the braneworld from compact stars

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    According to the braneworld idea, ordinary matter is confined on a 3-dimensional space (brane) that is embedded in a higher-dimensional space-time where gravity propagates. In this work, after reviewing the limits coming from general relativity, finiteness of pressure and causality on the brane, we derive observational constraints on the braneworld parameters from the existence of stable compact stars. The analysis is carried out by solving numerically the brane-modified Tolman-Oppenheimer-Volkoff equations, using different representative equations of state to describe matter in the star interior. The cases of normal dense matter, pure quark matter and hybrid matter are considered.Comment: 13 pages, 11 figures, 2 tables; new EoS considered, references and comments adde

    Axially deformed solution of the Skyrme-Hartree-Fock-Bogolyubov equations using the transformed harmonic oscillator basis (III) hfbtho (v3.00): a new version of the program

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    We describe the new version 3.00 of the code HFBTHO that solves the nuclear Hartree-Fock (HF) or Hartree-Fock-Bogolyubov (HFB) problem by using the cylindrical transformed deformed harmonic oscillator basis. In the new version, we have implemented the following features: (i) the full Gogny force in both particle-hole and particle-particle channels, (ii) the calculation of the nuclear collective inertia at the perturbative cranking approximation, (iii) the calculation of fission fragment charge, mass and deformations based on the determination of the neck (iv) the regularization of zero-range pairing forces (v) the calculation of localization functions (vi)MPI interface for large-scale mass table calculations.Comment: 29 pages, 3 figures, 4 tables; Submitted to Computer Physics Communication

    Towards Sustainable Development of Small-Scale Fisheries in the Philippines: Experiences and Lessons Learned from Eight Regional Sites

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    The focus of this paper is on the governance of small-scale or municipal fisheries in the Philippines in light of the critical role they play in the livelihoods of coastal communities and in the nation as a whole. The information and insights presented in this lessons learned brief derive from the project entitled Strengthening Governance and Sustainability of Small-Scale Fisheries Management in the Philippines: An Ecosystem Approach. The project was funded principally by the Department of Agriculture's Bureau of Agricultural Research (DA-BAR), and implemented from 2008 to 2011 by WorldFish in collaboration with the Department of Science and Technology (DOST) and selected partners. The underlying project's goal was to 'strengthen governance and sustainability of small-scale fisheries management in the Philippines.' There were a variety of objectives spread across two project phases but the primary objectives relevant to this brief include: (1) identifying issues at project sites and assessing potential for an ecosystem based approach to fisheries management, and (2) assessing current fisheries management practices at different levels of governance and identifying best practices. The purposes of this paper are twofold. First, it aims to provide brief highlights of the project findings; second, it aims to present the lessons learned in project implementation covering substantive sectoral concerns as well as methodological issues. It wraps up with some strategic directions that need to be undertaken to reverse the deteriorating conditions of small-scale fisheries (SSF) while at the same time promoting their sustainable development

    Efficient measurement-based quantum computing with continuous-variable systems

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    We present strictly efficient schemes for scalable measurement-based quantum computing using continuous-variable systems: These schemes are based on suitable non-Gaussian resource states, ones that can be prepared using interactions of light with matter systems or even purely optically. Merely Gaussian measurements such as optical homodyning as well as photon counting measurements are required, on individual sites. These schemes overcome limitations posed by Gaussian cluster states, which are known not to be universal for quantum computations of unbounded length, unless one is willing to scale the degree of squeezing with the total system size. We establish a framework derived from tensor networks and matrix product states with infinite physical dimension and finite auxiliary dimension general enough to provide a framework for such schemes. Since in the discussed schemes the logical encoding is finite-dimensional, tools of error correction are applicable. We also identify some further limitations for any continuous-variable computing scheme from which one can argue that no substantially easier ways of continuous-variable measurement-based computing than the presented one can exist.Comment: 13 pages, 3 figures, published versio

    Two and three electrons in a quantum dot: 1/|J| - expansion

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    We consider systems of two and three electrons in a two-dimensional parabolic quantum dot. A magnetic field is applied perpendicularly to the electron plane of motion. We show that the energy levels corresponding to states with high angular momentum, J, and a low number of vibrational quanta may be systematically computed as power series in 1/|J|. These states are relevant in the high-B limit.Comment: LaTeX, 15 pages,6 postscript figure
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