702 research outputs found
Generalized entropies and corresponding holographic dark energy models
Using Tsallis statistics and its relation with Boltzmann entropy, the Tsallis
entropy content of black holes is achieved, a result in full agreement with a
recent study (Phys. Lett. B 794, 24 (2019)). In addition, employing Kaniadakis
statistics and its relation with that of Tsallis, the Kaniadakis entropy of
black holes is obtained. The Sharma-Mittal and R\'{e}nyi entropy contents of
black holes are also addressed by employing their relations with Tsallis
entropy. Thereinafter, relying on the holographic dark energy hypothesis and
the obtained entropies, two new holographic dark energy models are introduced
and their implications on the dynamics of a flat FRW universe are studied when
there is also a pressureless fluid in background. In our setup, the apparent
horizon is considered as the IR cutoff, and there is not any mutual interaction
between the cosmic fluids. The results indicate that the obtained cosmological
models have ) notable powers to describe the cosmic evolution from the
matter-dominated era to the current accelerating universe, and ) suitable
predictions for the universe age
A Note on Tsallis Holographic Dark Energy
We explore the effects of considering various infrared (IR) cutoffs,
including the particle horizon, Ricci horizon and Granda-Oliveros (GO) cutoffs,
on the properties of Tsallis holographic dark energy (THDE) model, proposed
inspired by Tsallis generalized entropy formalism \cite{THDE}. Interestingly
enough, we find that for the particle horizon as IR cutoff, the obtained THDE
model can describe the accelerated universe. This is in contrast to the usual
HDE model which cannot lead to an accelerated universe, if one consider the
particle horizon as IR cutoff. We also investigate the cosmological
consequences of THDE under the assumption of a mutual interaction between the
dark sectors of the Universe. It is shown that the evolution history of the
Universe can be described by these IR cutoffs and thus the current cosmic
acceleration can also been realized. The sound instability of THDE models for
each cutoff are also explored, separately.Comment: 12 pages, 31 figure
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