January 29, 2011

Holographic unification of dark matter and dark energy

Arxiv - Holographic unification of dark matter and dark energy

Using a new version of the holographic principle, a constant term was introduced, which conduces to the description of the standard cosmological LCDM model, and unifies under the same concept the dark matter and dark energy phenomena. The obtained model improves the results of previously considered holographic models based on local quantities. The inclusion of constant term is interpreted as a natural first approximation for the infrared cutoff which is associated with the vacuum energy, and the additional terms guarantee an appropriate evolutionary scenario that fits the astrophysical observations. The model allows to reproduce the standard LCDM model without explicitly introducing matter content, and using only geometrical quantities. It is also obtained that the model may describe the dark energy beyond the standard LCDM.

We have shown that the holographic principle, may conduce to the description of the fundamental standard model of the current cosmology, and unify under the same concept the dark matter and dark energy phenomena without previously introducing any matter coontent. The proposed holographic model, which incorporates a constant term has notorious advantages with respect to the previous models based on
local quantities. This holographic principle also describes a deviation from the LCDM model, allowing the possibility of describing more exotic behavior of the universe with the DE EoS crossing the phantom barrier. This new model could be represented as LCDM*, where * indicates the deviation from the standard LCDM model. Adding this constant term to the IR cut-o may improve even models like the Hubble scale which was unable to produce accelerated expansion. In this case if we add
a constant term to the squared Hubble scale, we can describe the LCDM model (in
this case we should add matter content). It was shown that the astrophysical data
xes the combination {formula}. This means that one of the parameters or still free. To x the remaining parameter we use geometrical criteria in order to convert the last two terms in a term proportional to the Ricci scalar. In short, we can highlight the following important results: The dark matter and dark energy concepts are uni ed in a simple geometrical way. The introduction of a cosmological constant term in the frame of the holographic principle attributes quantum gravity nature to the cosmological constant. The model goes beyond the standard LCDM theory, allowing for a description of the cosmological quintom behavior (LCDM*), which is also supported by current astrophysical observations.
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