218 research outputs found

    Distributed entanglement induced by dissipative bosonic media

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    We describe a scheme with analytic result that allows to generate steady-state entanglement for two atoms over a dissipative bosonic medium. The resonant coupling between the mediating bosonic mode and cavity modes produces three collective atomic decay channels. This dissipative dynamics, together with the unitary process induced by classical microwave fields, drives the two atoms to the symmetric or asymmetric entangled steady state conditional upon the choice of the phases of the microwave fields. The effects on the steady-state entanglement of off-resonance mediating bosonic modes are analyzed. The entanglement can be obtained with high fidelity regardless of the initial state and there is a linear relation in the scaling of the fidelity with the cooperativity parameter. The fidelity is insensitive to the fluctuation of the Rabi frequencies of the classical driving fields.Comment: to appear in Europhysics Letter

    Effects of low-molecular-weight heparin and unfractionated heparin on traumatic disseminated intravascular coagulation

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    Purpose: To explore the effects of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) on traumatic disseminated  intravascular coagulation (DIC).Methods: A total of 77 cases of severe trauma (APACHE II score: 5 – 10) with DIC were collected and randomly assigned to one of three groups: LMWH treatment - 26 cases were subcutaneously injected with LMWH (75–150 units/kg/d); UFH treatment - 25 cases were subcutaneously  injected with UFH (100 – 250 units/kg/d); control - 26 cases supplemented with blood coagulation factor only. Daily mortality in the intensive care unit (ICU), hospitalization time, bleeding rate, thrombin time, prothrombin time, activated partial thromboplastin time, and levels of fibrinogen, antithrombin III (ATIII), and D-dimer were recorded and analyzed.Results: In ICU, LMWH and UFH treatments resulted in lower mortality than in the control group. In addition, hospitalization time was longer in patients treated with LMWH and UFH than in control patients. No significant  differences were found between LMWH-treated and control patients in terms of bleeding rate, but UFH-treated patients had lower bleeding rates than control patients. Multifactor analysis indicate a strong relationship between ATIII levels and bleeding rate.Conclusion: The results indicate that low-dose UFH and LMWH are effective options for the treatment of DIC.Keywords: Trauma, Disseminated intravascular coagulation, Unfractionated heparin, Low-molecularweight heparin, Fibrinogen, Antithrombi

    Theoretical understanding of correlation between magnetic phase transition and the superconducting dome in high-Tc cuprates

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    Many issues concerning the origin of high-temperature superconductivity (HTS) are still under debate. For example, how the magnetic ordering varies with doping and its relationship with the superconducting temperature; and why the maximal Tc always occurs near the quantum critical point. In this paper, taking hole-doped La2CuO4 as a classical example, we employ the first-principles band structure and total energy calculations and Monte Carlo simulations to explore how the symmetry-breaking magnetic ground state evolves with hole doping and the origin of a dome-shaped superconductivity region in the phase diagram. We demonstrate that the local antiferromagnetic ordering and doping play key roles in determining the electron-phonon coupling, thus Tc. Initially, the La2CuO4 possesses a checkerboard local antiferromagnetic ground state. As the hole doping increases, Tc increases with the increase of the density of states at the Fermi surface. But as the doping increases further, the strength of the antiferromagnetic interaction weakens. At the critical doping level, a magnetic phase transition occurs that reduces the local antiferromagnetism-assisted electron-phonon coupling, thus diminishing the Tc. The superconductivity disappears in the heavily overdoped region when the antiferromagnetic ordering disappears. These observations could account for why cuprates have a dome-shaped superconductivity region in the phase diagram. Our study, thus, contributes to a fundamental understanding of the correlation between doping, local magnetic ordering, and superconductivity of HTS.Comment: 14 pages, 3 figures in the main text; 11 pages, 7 figures in the supplementary material
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