5,016 research outputs found
Self-Organized Cooperative Criticality in Coupled Complex Systems
We show that the coupled complex systems can evolve into a new kind of
self-organized critical state where each subsystem is not critical, however,
they cooperate to be critical. This criticality is different from the classical
BTW criticality where the single system itself evolves into a critical state.
We also find that the outflows can be accumulated in the coupled systems. This
will lead to the emergency of spatiotemporal intermittency in the critical
state
Statefinder hierarchy exploration of the extended Ricci dark energy
We apply the statefinder hierarchy plus the fractional growth parameter to
explore the extended Ricci dark energy (ERDE) model, in which there are two
independent coefficients and . By adjusting them, we plot
evolution trajectories of some typical parameters, including Hubble expansion
rate , deceleration parameter , the third and fourth order hierarchy
and and fractional growth parameter ,
respectively, as well as several combinations of them. For the case of variable
and constant , in the low-redshift region the evolution
trajectories of are in high degeneracy and that of separate somewhat.
However, the CDM model is confounded with ERDE in both of these two
cases. and , especially the former, perform much better.
They can differentiate well only varieties of cases within ERDE except
CDM in the low-redshift region. For high-redshift region, combinations
can break the degeneracy. Both of
and have the ability to
discriminate ERDE with from CDM, of which the degeneracy
cannot be broken by all the before-mentioned parameters. For the case of
variable and constant , and can
only discriminate ERDE from CDM. Nothing but pairs
and can discriminate not only
within ERDE but also ERDE from CDM. Finally we find that
is surprisingly a better choice to discriminate within ERDE itself, and ERDE
from CDM as well, rather than .Comment: 8 pages, 14 figures; published versio
Comparing holographic dark energy models with statefinder
We apply the statefinder diagnostic to the holographic dark energy models,
including the original holographic dark energy (HDE) model, the new holographic
dark energy model, the new agegraphic dark energy (NADE) model, and the Ricci
dark energy model. In the low-redshift region the holographic dark energy
models are degenerate with each other and with the CDM model in the
and evolutions. In particular, the HDE model is highly degenerate
with the CDM model, and in the HDE model the cases with different
parameter values are also in strong degeneracy. Since the observational data
are mainly within the low-redshift region, it is very important to break this
low-redshift degeneracy in the and diagnostics by using some
quantities with higher order derivatives of the scale factor. It is shown that
the statefinder diagnostic is very useful in breaking the low-redshift
degeneracies. By employing the statefinder diagnostic the holographic dark
energy models can be differentiated efficiently in the low-redshift region. The
degeneracy between the holographic dark energy models and the CDM
model can also be broken by this method. Especially for the HDE model, all the
previous strong degeneracies appearing in the and diagnostics are
broken effectively. But for the NADE model, the degeneracy between the cases
with different parameter values cannot be broken, even though the statefinder
diagnostic is used. A direct comparison of the holographic dark energy models
in the -- plane is also made, in which the separations between the models
(including the CDM model) can be directly measured in the light of the
current values of the models.Comment: 8 pages, 8 figures; accepted by European Physical Journal C; matching
the publication versio
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