95,002 research outputs found

    Mode entanglement of electrons in the one-dimensional Frenkel-Kontorova model

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    We study the mode entanglement in the one-dimensional Frenkel-Kontorova model, and found that behaviors of quantum entanglement are distinct before and after the transition by breaking of analyticity. We show that the more extended the electron is, the more entangled the corresponding state. Finally, a quantitative relation is given between the average square of the concurrence quantifying the degree of entanglement and the participation ratio characterizing the degree of localization.Comment: 4 pages, 4 figures. V

    Anomalous Paramagnetic Magnetization in Mixed State of CeCoIn5_5 single crystals

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    Magnetization and torque measurements were performed on CeCoIn5_5 single crystals to study the mixed-state thermodynamics. These measurements allow the determination of both paramagnetic and vortex responses in the mixed-state magnetization. The paramagnetic magnetization is suppressed in the mixed state with the spin susceptibility increasing with increasing magnetic field. The dependence of spin susceptibility on magnetic field is due to the fact that heavy electrons contribute both to superconductivity and paramagnetism and a large Zeeman effect exists in this system. No anomaly in the vortex response was found within the investigated temperature and field range

    A portable MBE system for in situ X-Ray investigations at synchrotron beamlines

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    A portable synchrotron MBE system is designed and applied for in situ investigations. The growth chamber is equipped with all the standard MBE components such as effusion cells with shutters, main shutter, cooling shroud, manipulator, RHEED setup and pressure gauges. The characteristic feature of the system is the beryllium windows which are used for in situ x-ray measurements. An UHV sample transfer case allows in-vacuo transfer of samples prepared elsewhere. We describe the system design and demonstrate it's performance by investigating the annealing process of buried InGaAs self organized quantum dots

    iCosmo: an Interactive Cosmology Package

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    Aims: The interactive software package iCosmo, designed to perform cosmological calculations is described. Methods: iCosmo is a software package to perform interactive cosmological calculations for the low redshift universe. Computing distance measures, the matter power spectrum, and the growth factor is supported for any values of the cosmological parameters. It also computes derived observed quantities for several cosmological probes such as cosmic shear, baryon acoustic oscillations and type Ia supernovae. The associated errors for these observables can be derived for customised surveys, or for pre-set values corresponding to current or planned instruments. The code also allows for the calculation of cosmological forecasts with Fisher matrices which can be manipulated to combine different surveys and cosmological probes. The code is written in the IDL language and thus benefits from the convenient interactive features and scientific library available in this language. iCosmo can also be used as an engine to perform cosmological calculations in batch mode, and forms a convenient adaptive platform for the development of further cosmological modules. With its extensive documentation, it may also serve as a useful resource for teaching and for newcomers in the field of cosmology. Results: The iCosmo package is described with various examples and command sequences. The code is freely available with documentation at http://www.icosmo.org, along with an interactive web interface and is part of the Initiative for Cosmology, a common archive for cosmological resources.Comment: 6 pages including 2 tables and 4 figures. Accepted and published in Astronomy and Astrophysics. Public code and further resources available at http://www.icosmo.or

    Pairing Symmetry of CeCoIn5_5 Detected by In-plane Torque Measurements

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    In-plane torque measurements were performed on heavy fermion CeCoIn5_5 single crystals in the temperature TT range 1.8 K T10\leq T \leq 10 K and applied magnetic field HH up to 14 T. The normal-state torque is given by τnH4(1+T/TK)1sin4ϕ\tau_n \propto H^4(1+T/T_K)^{-1}\sin 4\phi. The reversible part of the mixed-state torque, obtained after subtracting the corresponding normal state torque, shows also a four-fold symmetry. In addition, sharp peaks are present in the irreversible torque at angles of π/\pi/4, 3π\pi/4, 5π\pi/4, 7π\pi/4, etc. Both the four-fold symmetry in the reversible torque and the sharp peaks in the irreversible torque of the mixed state imply dxyd_{xy} symmetry of the superconducting order parameter. The field and temperature dependences of the reversible mixed-state torque provide further evidence for dxyd_{xy} wave symmetry. The four-fold symmetry in the normal state has a different origin since it has different field and temperature dependences than the one in the mixed state. The possible reasons of the normal state four-fold symmetry are discussed

    Nonequilibrium Phase Transitions of Vortex Matter in Three-Dimensional Layered Superconductors

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    Large-scale simulations on three-dimensional (3D) frustrated anisotropic XY model have been performed to study the nonequilibrium phase transitions of vortex matter in weak random pinning potential in layered superconductors. The first-order phase transition from the moving Bragg glass to the moving smectic is clarified, based on thermodynamic quantities. A washboard noise is observed in the moving Bragg glass in 3D simulations for the first time. It is found that the activation of the vortex loops play the dominant role in the dynamical melting at high drive.Comment: 3 pages,5 figure

    Do Local Production, Organic Certification, Nutritional Claims, and Product Branding Pay in Consumer Food Choices?

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    This research furthers the assessment of consumer demand for locally produced foods, while also considering a host of other food attributes that may interact to influence consumer utility. Using stated preference data from a choice-based conjoint analysis survey instrument, we estimate willingness-to-pay for processed food products (blackberry jam) that are differentiated with respect to their branding, the location of their production, certification as organically produced, branding as a product of a small family farming association, and carrying a State Proud certification. Although price is the most important single attribute influencing consumer choice for our sample, consumers also were willing to pay more for food products produced in their state or in a well identified multistate region. Our sample was more willing to purchase organic products, although there was an indication of some confusion as to the meaning of the NOP organic logo. Our results also supported the notion that consumers are willing to support small family farms with purchases if the product is clearly labeled as a product of small farms. These conclusions have important is significant has important policy and merchandising strategy implications.Conjoint analysis, Choice experiment, Locally produced food, Organic foods, Product differentiation, Produce marketing, State Proud programs, Willingness-to-pay, Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Marketing, Q11, Q13,
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