1,919 research outputs found

    Density functional theory of vortex lattice melting in layered superconductors: a mean-field--substrate approach

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    We study the melting of the pancake vortex lattice in a layered superconductor in the limit of vanishing Josephson coupling. Our approach combines the methodology of a recently proposed mean-field substrate model for such systems with the classical density functional theory of freezing. We derive a free-energy functional in terms of a scalar order-parameter profile and use it to derive a simple formula describing the temperature dependence of the melting field. Our theoretical predictions are in good agreement with simulation data. The theoretical framework proposed is thermodynamically consistent and thus capable of describing the negative magnetization jump obtained in experiments. Such consistency is demonstrated by showing the equivalence of our expression for the density discontinuity at the transition with the corresponding Clausius-Clapeyron relation.Comment: 11 pages, 4 figure

    Nonequilibrium gas-liquid transition in the driven-dissipative photonic lattice

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    We study the nonequilibrium steady state of the driven-dissipative Bose-Hubbard model with Kerr nonlinearity. Employing a mean-field decoupling for the intercavity hopping JJ, we find that the steep crossover between low and high photon-density states inherited from the single cavity transforms into a gas−-liquid bistability at large cavity-coupling JJ. We formulate a van der Waals like gas−-liquid phenomenology for this nonequilibrium situation and determine the relevant phase diagrams, including a new type of diagram where a lobe-shaped boundary separates smooth crossovers from sharp, hysteretic transitions. Calculating quantum trajectories for a one-dimensional system, we provide insights into the microscopic origin of the bistability.Comment: 5 pages, 4 figures + Supplemental Material (2 pages, 2 figures

    New fixed point action for SU(3) lattice gauge theory

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    We present a new fixed point action for SU(3) lattice gauge theory, which has --- compared to earlier published fixed point actions --- shorter interaction range and smaller violations of rotational symmetry in the static q\bar{q}-potential even at shortest distances

    Endocarditis Prophylaxis: From Experimental Models to Human Recommendation

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    Animal models of endocarditis have helped understanding of the mode of action of antibiotics in prophylaxis. During bacteraemia, some microorganisms will adhere to damaged cardiac valves. The proportion of bacteria that will adhere depends largely on intrinsic properties of the strain. In the absence of antibiotics, the microorganisms will either be eliminated by local host defence mechanisms if the inoculum is low enough or will begin to grow approximately 2 h after the development of bacteraemia and endocarditis. In the presence of antibiotics, the growth of adherent bacteria is inhibited and local host defences have longer to eliminate the bacteria. In cases where the number of adherent bacteria is relatively low, a short period in inhibitory antibiotic activity (6 hours) is sufficient to eliminate the bacteria and lead to successful prophylaxis. If the number of bacteria is high, a longer duration of the inhibitory effect is necessary. These experimental data provide a rationale for practical recommendations for the prophylaxis of endocarditis in human
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