3,282 research outputs found

    Geometrical bounds on irreversibility in open quantum systems

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    Clausius inequality has deep implications for reversibility and the arrow of time. Quantum theory is able to extend this result for closed systems by inspecting the trajectory of the density matrix on its manifold. Here we show that this approach can provide an upper and lower bound to the irreversible entropy production for open quantum systems as well. These provide insights on the thermodynamics of the information erasure. Limits of the applicability of our bounds are discussed, and demonstrated in a quantum photonic simulator

    Effect of kinematics on final state interactions in (e,e'p) reactions

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    Recent data from experiment E97-006 at TJNAF using the 12C(e,e'p) reaction at very large missing energies and momenta are compared to a calculation of two-step rescattering. A comparison between parallel and perpendicular kinematics suggests that the effects of final state interactions can be strongly reduced in the former case.Comment: 10 pages, 3 figures, submitted to LP

    Bridging thermodynamics and metrology in non-equilibrium Quantum Thermometry

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    Single-qubit thermometry presents the simplest tool to measure the temperature of thermal baths with reduced invasivity. At thermal equilibrium, the temperature uncertainty is linked to the heat capacity of the qubit, however the best precision is achieved outside equilibrium condition. Here, we discuss a way to generalize this relation in a non-equilibrium regime, taking into account purely quantum effects such as coherence. We support our findings with an experimental photonic simulation.Comment: 7 pages, 4 figure

    Experimental Detection of Entanglement with Polarized Photons

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    We report on the first experimental realization of the entanglement witness for polarization entangled photons. It represents a recently discovered significant quantum information protocol which is based on few local measurements. The present demonstration has been applied to the so-called Werner states, a family of ''mixed'' quantum states that include both entangled and non entangled states. These states have been generated by a novel high brilliance source of entanglement which allows to continuously tune the degree of mixedness

    Effect of Stocking Rate and Grazing System on Fine and Superfine Merino Wool Production and Quality on Native Swards of Uruguay

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    Modern textile tendencies show that consumers prefer light, soft, resistant, natural, and comfortable clothes, for which fine and superfine wools are in great demand, particularly at the high value markets (Whiteley, 2003). The main objective of the present study was to define sustainable stocking rates and grazing systems on native swards for fine and superfine wool production in the Basaltic region of Uruguay

    One perception, two perspectives: measuring psychological contract dimensionality through the Psychological Contract Content Questionnaire

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    The present study aims to contribute to the validity strengthening of a psychological contract measure, assessing the dimensionality of the item structure of the Psychological Contract Content Questionnaire (PCCQ). According to the authors (De Vos, Buyens, & Schalk, 2003), the scale consists of two theoretical dimensions, one to measure perceived employer inducement (PEI) and the other to measure perceived employee contributions (PEC), both from the employee's perception, each divided into five content areas. Different structure models were tested in newcomers (police officers working in the Penitentiary Administration attending a one-year training) in two different stages of their entry: at their early entrance (three weeks, TI; 436 respondents) and after their encounter with the operative environment (eight months, T2; 519 respondents). Analyses were carried out using nonparametric item response theory (IRT) approach and multidimensional IRT approach. Results showed that psychological contract is a single latent construct that describes the general perception that the employee has about his/her relationship with the organization and reciprocal obligations fulfilment

    The Messenger Sector of SUSY Flavour Models and Radiative Breaking of Flavour Universality

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    The flavour messenger sectors and their impact on the soft SUSY breaking terms are investigated in SUSY flavour models. In the case when the flavour scale M is below the SUSY breaking mediation scale M_S, the universality of soft terms, even if assumed at M_S, is radiatively broken. We estimate this effect in a broad class of models. In the CKM basis that effect gives flavour off-diagonal soft masses comparable to the tree-level estimate based on the flavour symmetry.Comment: 24 pages, 3 figures. v3: minor changes in the text, typos corrected, version accepted for publication in JHE

    Heavy Scalar Top Quark Decays in the Complex MSSM: A Full One-Loop Analysis

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    We evaluate all two-body decay modes of the heavy scalar top quark in the Minimal Supersymmetric Standard Model with complex parameters (cMSSM) and no generation mixing. The evaluation is based on a full one-loop calculation of all decay channels, also including hard QED and QCD radiation. The renormalization of the complex parameters is described in detail. The dependence of the heavy scalar top quark decay on the relevant cMSSM parameters is analyzed numerically, including also the decay to Higgs bosons and another scalar quark or to a top quark and the lightest neutralino. We find sizable contributions to many partial decay widths and branching ratios. They are roughly of O(10%) of the tree-level results, but can go up to 30% or higher. These contributions are important for the correct interpretation of scalar top quark decays at the LHC and, if kinematically allowed, at the ILC. The evaluation of the branching ratios of the heavy scalar top quark will be implemented into the Fortran code FeynHiggs.Comment: 86 pages, 38 figures; minor changes, version published as Phys. Rev. D86 (2012) 03501

    Solving the mu problem with a heavy Higgs boson

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    We discuss the generation of the mu-term in a class of supersymmetric models characterized by a low energy effective superpotential containing a term lambda S H_1 H_2 with a large coupling lambda~2. These models generically predict a lightest Higgs boson well above the LEP limit of 114 GeV and have been shown to be compatible with the unification of gauge couplings. Here we discuss a specific example where the superpotential has no dimensionful parameters and we point out the relation between the generated mu-term and the mass of the lightest Higgs boson. We discuss the fine-tuning of the model and we find that the generation of a phenomenologically viable mu-term fits very well with a heavy lightest Higgs boson and a low degree of fine-tuning. We discuss experimental constraints from collider direct searches, precision data, thermal relic dark matter abundance, and WIMP searches finding that the most natural region of the parameter space is still allowed by current experiments. We analyse bounds on the masses of the superpartners coming from Naturalness arguments and discuss the main signatures of the model for the LHC and future WIMP searches.Comment: Extended discussion of the LHC phenomenology, as published on JHEP plus an addendum on the existence of further extremal points of the potential. 47 pages, 16 figure

    Regenera+.uy: Designing a Co-Innovation Process to Apply the Principles of Regenerative Livestock Production

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    Consumers around the world are beginning to demand products whose production systems have environmental guarantees. Among them, those derived from regenerative agriculture have a growing demand in many markets. A comprehensive environmental assessment was carried out in 9 case studies of mixed livestock production farms (cattle and sheep) in Uruguay as a basis for the development of a system redesign process following the principles of regenerative agriculture. The results show that emission intensity was 16.0, 10.5, and 49.2 kg CO2 eq kg-1 of beef, sheep meat, and greasy wool, respectively. Also, a simulation exercise shows a significative reduction of emission through animal genetic improvement. Soil carbon stocks (59.6 to 93.6 Mg ha-1) and the different level of biodiversity assessment show a very good situation with an Ecosystem Integrity Index above 3.5, which implies more a necessity to conserve rather than regenerate. Considering this analysis, the path that farmers begin to walk following the principles of regenerative agriculture is a challenge towards maximizing biological efficiency and environmental optimization through process technology application. All these indicators and the recommended good management practices will integrate into a protocol for making verifiable the prosses and the results
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