Eur. Phys. J. C (2019) 79:414
https://doi.org/10.1140/epjc/s10052-019-6934-x
Regular Article - Theoretical Physics
Stability analysis for cosmological models in f (R) gravity using
dynamical system analysis
Parth Shah
a
, Gauranga C. Samanta
b
Department of Mathematics, BITS Pilani K K Birla Goa Campus, Sancoale, Goa 403726, India
Received: 27 February 2019 / Accepted: 8 May 2019 / Published online: 16 May 2019
© The Author(s) 2019
Abstract Modified gravity theories have received increased
attention lately to understand the late time acceleration of
the universe. This viewpoint essentially modifies the geo-
metric components of the universe. Among numerous exten-
sion to Einstein’s theory of gravity, theories which include
higher order curvature invariant, and specifically the class
of f (R) theories, have received several acknowledgments.
In our current work we try to understand the late time
acceleration of the universe by modifying the geometry of
the space and using dynamical system analysis. The use
of this technique allows to understand the behavior of the
universe under several circumstances. Apart from that we
study the stability properties of the critical point and acceler-
ation phase of the universe which could then be analyzed
with observational data. We consider a particular model
f (R) = R − μR
c
(R/R
c
)
p
with 0 < p < 1,μ,R
c
> 0
for the study. As a first case we consider the matter and radi-
ation component of the universe with an assumption of no
interaction between them. Later, as a second case we take
matter, radiation and dark energy (cosmological constant)
where study on effects of linear, non-linear and no interac-
tion between matter and dark energy is considered and results
have been discussed in detail.
1 Introduction
Late time acceleration predicted by observational data have
opened major challenge in the modern cosmology [1,2]This
causes challenges and questions about limitations of a very
successful theory of last century, the general theory of relativ-
ity (GR) very prominent. One of the most fruitful approaches
so far has been the extended theories of gravity, which have
become a standard model in the study of gravitational interac-
tion. These extensions are based on corrections in Einstein’s
a
e-mail: parthshah2908@gmail.com
b
e-mail: gauranga81@gmail.com
theory. These kind of alternative gravitational theories are an
attempt to construct a semi-classical scheme in which GR and
most of its successful features can be recovered. This exten-
sion essentially consists of adding higher order curvature
invariants by modifying the Einstein–Hilbert (EH) action.
In the beginning of 1960’s there were indications about the
merits of this extensions as GR is not renormalizable and thus
can not be quantized conventionally. Utiyama and De Witt
[3] showed that renormalization demands higher order cur-
vature invariants in EH action. These theories created interest
among scientific community in higher order theories of grav-
ity, i.e. modifications of EH action to include higher order
curvature invariants with respect to Ricci scalar. These cor-
rections to GR were initially considered to be important only
at scales close to the Planck scale which is in very early uni-
verse and near black hole singularity and indeed there were
relevant studies in this attempt like [4,5]. However it was not
expected that these corrections could give significant effect
at low energies i.e. at large scales in the late universe. Recent
evidence from observational physics and cosmology has rev-
eled quite different picture of the universe. The latest CMBR
data indicate 4%, 20 % and 76% proportion of ordinary bary-
onic matter, dark matter and dark energy respectively [6–9].
The term dark matter refers to an unknown form of matter,
which has the clustering properties as ordinary matter but
has not yet been discovered experimentally. The term dark
energy is an unknown form of energy which is not only dis-
covered experimentally but even does not cluster like ordi-
nary baryonic matter. One could only distinguish them from
energy conditions as dark matter satisfy strong energy condi-
tion but dark energy does not [10]. This issue comes with the
early time accelerated epoch predicted by inflation which is
needed to address the horizon, flatness and monopole prob-
lem [11–14] as well as to provide a mechanism that gener-
ates inhomogeneities which leads to formation of large scale
structure [15]. Apart from that between these two accelera-
tion epoch, there should be a period of decelerated expansion
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