Energy Conditions in $f(P)$ Gravity

Abstract

f (P ) gravity is a novel extension of ECG in which the Ricci scalar in the action is replaced by a function of the curvature invariant P which represents the contractions of the Riemann tensor at the cubic order [9]. The present work is concentrated on bounding some f (P ) gravity models using the concept of energy conditions where the functional forms of f (P ) are represented as a) f (P ) = α √ P , and b) f (P ) = α exp(P ), where α 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 −1 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 f (P ) theory of gravity to be a promising modified theory of gravitation.

Baryogenesis in $f(P)$ Gravity

“…Since then, f (P ) gravity is being widely used to study late-time acceleration, black holes, and inflation. Recently, tight constraints on f (P ) gravity have been reported from the energy conditions [9]. It is well known that there is an asymmetry in the matter content of the Universe where most of the objects we observe are composed of matter while we do not see any such objects composed primarily of antimatter.…”

“…Thereafter, f (P ) gravity have been successfully applied to explain the late-time acceleration [5,6], spherically symmetric black hole solutions [7], and inflation [8]. Recently, tight constraints on f (P ) gravity have been reported from the energy conditions [9]. It is quite well known and concurrently mysterious to note that the objects and structures in the Universe are composed of matter and that the Universe only contains a trifling amount of antimatter [10].…”

Energy conditions in extended f(R, G, T) gravity

“…Sadeghi et al [66] looked at certain f (G) gravity models that obey WECs and strong energy conditions (SECs) in a time when the late-time de-Sitter solution was stable. Banijamali et al [67] studied the WECs distribution for a class of consistent f (G) models and predicted that a power law model of kind f (G) = òG n would satisfy the WECs when ò < 0 was set. The various aspects of charged compact stars is analyzed in Ref.…”