30 research outputs found
Growth Rate and Configurational Entropy in Tsallis Holographic Dark Energy
In this work, we analyzed the effect of different prescriptions of the IR
cutoffs, namely the Hubble horizon cutoff, particle horizon cutoff, Granda and
Oliveros horizon cut off, and the Ricci horizon cutoff on the growth rate of
clustering for the Tsallis holographic dark energy (THDE) model in an FRW
universe devoid of any interactions between the dark Universe. Furthermore, we
used the concept of configurational entropy to derive constraints
(qualitatively) on the model parameters for the THDE model in each IR cutoff
prescription from the fact that the rate of change of configurational entropy
hits a minimum at a particular scale factor which indicate precisely
the epoch of dark energy domination predicted by the relevant cosmological
model as a function of the model parameter(s). By using the current
observational constraints on the redshift of transition from a decelerated to
an accelerated Universe, we derived constraints on the model parameters
appearing in each IR cutoff definition and on the non-additivity parameter
characterizing the THDE model and report the existence of simple
linear dependency between and in each IR cutoff setup
Baryogenesis in Gravity
In this work, we investigate gravitational baryogenesis in the framework of
gravity to understand the applicability of this class of modified
gravity in addressing the baryon asymmetry of the Universe. For the analysis,
we set where is the model parameter. We found that
in gravity, the CP-violating interaction acquires a modification through
the addition of the nontopological cubic term in addition to the Ricci
scalar and the mathematical expression of the baryon-to-entropy ratio
depends not only on the time derivative of but also the time derivative of
. Additionally, we also investigate the consequences of a more complete and
generalized CP-violating interaction proportional to instead of in
addressing the baryon asymmetry of the Universe. For this type of interaction,
we report that the baryon-to-entropy ratio is proportional to ,
and . We report that for both of these cases, rational
values of and generate acceptable baryon-to-entropy ratios
compatible with observations
Energy Conditions in Gravity
gravity is a novel extension of ECG in which the Ricci scalar in the
action is replaced by a function of the curvature invariant which
represents the contractions of the Riemann tensor at the cubic order \cite{p}.
The present work is concentrated on bounding some gravity models using
the concept of energy conditions where the functional forms of are
represented as \textbf{a)} , and \textbf{b)} , where is the sole model parameter. Energy conditions
are interesting linear relationships between pressure and density and have been
extensively employed to derive interesting results in Einstein's gravity, and
are also an excellent tool to impose constraints on any cosmological model. To
place the bounds, we ensured that the energy density must remain positive, the
pressure must remain negative, and the EoS parameter must attain a value close
to to make sure that the bounds respect the accelerated expansion of the
Universe and are also in harmony with the latest observational data. We report
that for both the models, suitable parameter spaces exist which satisfy the
aforementioned conditions and therefore posit the theory of gravity to
be a promising modified theory of gravitation
Inflation in mimetic gravity
In this paper, we employ mimetic gravity coupled with Lagrange
multiplier and mimetic potential to yield viable inflationary cosmological
solutions consistent with latest Planck and BICEP2/Keck Array data. We present
here three viable inflationary solutions of the Hubble parameter ()
represented by ,
, and , where , , , , are
free parameters, and represents the number of e-foldings. We carry out the
analysis with the simplest minimal function of the form , where is the model parameter. We report that for the chosen
gravity model, viable cosmologies are obtained compatible with
observations by conveniently setting the Lagrange multiplier and the mimetic
potential
Configurational Entropy in Chaplygin Gas Models
The present work investigates the dissipation of configurational entropy in
some of the most widely studied Chaplygin gas models, such as the generalized
Chaplygin gas and the modified Chaplygin gas, and communicate the existence of
a wide range of parameter space which gives rise to a viable dissipation of
configurational entropy, and therefore certifying its time derivative to hit a
minimum at a scale factor which complies with the current observational
constraints on the redshift of transition from a dust to an accelerated
Universe