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Víctor H. Cárdenas

Publications and source records attributed to Víctor H. Cárdenas.

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Cosmic slowing down of acceleration for several dark energy parametrizations

We further investigate slowing down of acceleration of the universe scenario for five parametrizations of the equation of state of dark energy using four sets of supernovae data. In a maximal probability analysis we also use the baryon acoustic oscillation and cosmic microwave background observations. We found the low redshift transition of the deceleration parameter appears, independently of the parametrization, using supernovae data alone except for the Union 2.1 sample. This feature disappears once we combine the supernova data with high redshift data. We conclude that the rapid variation of the deceleration parameter is independent of the parametrization. We also found more evidence for a tension among the supernovae samples, as well as for the low and high redshift data.

astro-ph.CO↗

Semi-holographic model revisited

In a recent work Zhang, Li and Noh [Phys. Lett. B {\bf 694}, 177 (2010)]proposed a model for dark energy assuming this component strictly obeys the holographic principle. They performed a dynamical system analysis, finding a scaling solution which is helpful to solve the coincidence problem. However they need explicitly a cosmological constant. In this paper we derive an explicit analytical solution, without $Λ$, that shows agreement with the Supernovae data. However this solution is not physical because violate all the energy conditions.

astro-ph.CO↗