29,037 research outputs found

    What Should We Learn From Early Hemodialysis Allocation About How We Should Be Using ECMO?

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    Early hemodialysis allocation deliberations should inform our current considerations of what constitutes reasonable uses of extracorporeal membrane oxygenation. Deliberative democracy can be used as a strategy to gather a plurality of views, consider criteria, and guide policy making

    Dependence Estimation and Visualization in Multivariate Extremes with Applications to Financial Data

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    We investigate extreme dependence in a multivariate setting with special emphasis on financial applications. We introduce a new dependence function which allows us to capture the complete extreme dependence structure and present a nonparametric estimation procedure. The new dependence function is compared with existing measures including the spectral measure and other devices measuring extreme dependence. We also apply our method to a financial data set of zero coupon swap rates and estimate the extreme dependence in the data

    Lindblad dynamics of the quantum spherical model

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    The purely relaxational non-equilibrium dynamics of the quantum spherical model as described through a Lindblad equation is analysed. It is shown that the phenomenological requirements of reproducing the exact quantum equilibrium state as stationary solution and the associated classical Langevin equation in the classical limit g0g\to 0 fix the form of the Lindblad dissipators, up to an overall time-scale. In the semi-classical limit, the models' behaviour become effectively the one of the classical analogue, with a dynamical exponent z=2z=2, and an effective temperature TeffT_{\rm eff}, renormalised by the quantum coupling gg. A distinctive behaviour is found for a quantum quench, at zero temperature, deep into the ordered phase ggc(d)g\ll g_c(d), for d>1d>1 dimensions. Only for d=2d=2 dimensions, a simple scaling behaviour holds true, with a dynamical exponent z=1z=1, while for dimensions d2d\ne 2, logarithmic corrections to scaling arise. The spin-spin correlator, the growing length scale and the time-dependent susceptibility show the existence of several logarithmically different length scales.Comment: 61 pages, 14 figure

    Analysis of the conditional mutual information in ballistic and diffusive non-equilibrium steady-states

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    The conditional mutual information (CMI) I(A ⁣: ⁣CB)\mathcal{I}(A\! : \! C|B) quantifies the amount of correlations shared between AA and CC \emph{given} BB. It therefore functions as a more general quantifier of bipartite correlations in multipartite scenarios, playing an important role in the theory of quantum Markov chains. In this paper we carry out a detailed study on the behavior of the CMI in non-equilibrium steady-states (NESS) of a quantum chain placed between two baths at different temperatures. These results are used to shed light on the mechanisms behind ballistic and diffusive transport regimes and how they affect correlations between different parts of a chain. We carry our study for the specific case of a 1D bosonic chain subject to local Lindblad dissipators at the boundaries. In addition, the chain is also subject to self-consistent reservoirs at each site, which are used to tune the transport between ballistic and diffusive. As a result, we find that the CMI is independent of the chain size LL in the ballistic regime, but decays algebraically with LL in the diffusive case. Finally, we also show how this scaling can be used to discuss the notion of local thermalization in non-equilibrium steady-states
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