218 research outputs found
Distributed entanglement induced by dissipative bosonic media
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
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
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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