5,864 research outputs found
Apparent horizon and gravitational thermodynamics of Universe in the Eddington-Born-Infeld theory
The thermodynamics of Universe in the Eddington-Born-Infeld (EBI) theory was
restudied by utilizing the holographic-style gravitational equations that
dominate the dynamics of the cosmical apparent horizon and the
evolution of Universe. We started in rewriting the EBI action of the Palatini
approach into the Bigravity-type action with an extra metric . With
the help of the holographic-style dynamical equations, we discussed the
property of the cosmical apparent horizon including timelike,
spacelike and null characters, which depends on the value of the parameter of
state in EBI Universe. The unified first law for the gravitational
thermodynamics and the total energy differential for the open system enveloped
by in EBI Universe were obtained. Finally, applying the
positive-heat-out sign convention, we derived the generalized second law of
gravitational thermodynamics in EBI universe.Comment: 23 pages, 0 figure
Efficient Numerical Evaluation of Feynman Integral
Feynman loop integrals are a key ingredient for the calculation of higher
order radiation effects, and are responsible for reliable and accurate
theoretical prediction. We improve the efficiency of numerical integration in
sector decomposition by implementing a quasi-Monte Carlo method associated with
the CUDA/GPU technique. For demonstration we present the results of several
Feynman integrals up to two loops in both Euclidean and physical kinematic
regions in comparison with those obtained from FIESTA3. It is shown that both
planar and non-planar two-loop master integrals in the physical kinematic
region can be evaluated in less than half a minute with
accuracy, which makes the direct numerical approach viable for precise
investigation of higher order effects in multi-loop processes, e.g. the
next-to-leading order QCD effect in Higgs pair production via gluon fusion with
a finite top quark mass.Comment: 8 pages, 5 figures, published in Chinese Physics
(3,6-Dibromo-o-phenylÂene)dimethanol
The title compound, C8H8Br2O2, was synthesized from the hydrolysis of 1,4-dibromo-2,3-bisÂ(bromoÂmethÂyl)benzene. One intraÂmolecular O—H⋯O and two intraÂmolecular C—H⋯Br interÂactions occur. In the crystal, molÂecules are linked into a chain running parallel to [010]. Adjacent chains are linked into a two-dimensional layer by a combination of interÂmolecular O—H⋯O hydrogen bonds and C—H⋯π interÂactions
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