565,916 research outputs found

    Chiral expansion of the π0γγ\pi^0\rightarrow\gamma\gamma decay width

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    A chiral field theory of mesons has been applied to study the contribution of the current quark masses to the π0γγ\pi^0\rightarrow\gamma\gamma decay width at the next leading order. 2%2\% enhancement has been predicted and there is no new parameter.Comment: 9 page

    Classification of Arbitrary Multipartite Entangled States under Local Unitary Equivalence

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    We propose a practical method for finding the canonical forms of arbitrary dimensional multipartite entangled states, either pure or mixed. By extending the technique developed in one of our recent works, the canonical forms for the mixed NN-partite entangled states are constructed where they have inherited local unitary symmetries from their corresponding N+1N+1 pure state counterparts. A systematic scheme to express the local symmetries of the canonical form is also presented, which provides a feasible way of verifying the local unitary equivalence for two multipartite entangled states.Comment: 22 pages; published in J. Phys. A: Math. Theo

    Systematic Derivation for Quadrature Oscillators Using CCCCTAs

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    According to 16 nullor-mirror models of the current-controlled current conveyor transconductance amplifier (CCCCTA) and using nodal admittance matrix (NAM) expansion method, three different classes of the double-mode quadrature oscillators employed CCCCTAs and two grounded capacitors are synthesized. The class I oscillators have 32 different forms, the class II oscillators have 16 different forms, and the class III oscillators have four different forms. In all, 52 quadrature oscillators using CCCCTAs are obtained. Having used canonic number of components, the circuits are easy to be integrated and the condition for oscillation and the frequency of oscillation can be tuned by tuning bias currents of the CCCCTAs. The circuit analysis and simulation results have been included to support the generation method

    The influence of reconstruction criteria on the sensitive probes of the symmetry potential

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    Different criteria of constructing clusters and tracing back Δ\Delta resonances from the intermediate-energy neutron-rich HICs are discussed by employing the updated UrQMD transport model. It is found that both the phase-space and the coordinate-density criteria affect the single and the double neutron/proton ratios of free nucleons at small transverse momenta, but the influence becomes invisible at large transverse momenta. The effect of different methods of reconstructing freeze-out Δ\Deltas on the Δ0/Δ++\Delta^0/\Delta^{++} ratio is strong in a large kinetic energy region.Comment: 8 pages, 7 fig

    Duration of heart failure and the risk of atrial fibrillation: different mechanisms at different times?

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    Chronic heart failure increases the risk of atrial fibrillation (AF), with the prevalence of AF paralleling the severity of heart failure.1 Factors that underlie this increased susceptibility to AF may include electrical, structural, and neurohumoral changes.2 In AF, it is recognized that atrial electrophysiological remodelling occurs and contributes to the perpetuation of the arrhythmia, most notably the decrease of effective refractory period (ERP) which predisposes to re-entry by shortening the wavelength. Does heart failure cause similar changes in atrial electrophysiology that predispose to the arrhythmia

    The gravitational field of a global monopole

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    We present an exact solution to the non-linear equation which describes a global monopole in the flat space. We re-examine the metric and the geodesics outside the global monopole. We will see that a global monopole produces a repulsive gravitational field outside the core in addition to a solid angular deficit. The lensing property of the global monopole and the global monopole-antimonopole annihilation mechanism are studied.Comment: 8 pages, no figure