A Note on Varying G and Λ in Chern–Simons Modified Gravity

Abstract

We have considered the holographic dark energy and modified holographic Ricci dark energy models to analyze the time-dependent gravitational constant G(t) and cosmological constant Λ(t) in the context of Chern–Simons modified gravity theory. The FRW metric is used to examine the physical and kinematical properties of these models, which predicted the accelerated expansion phase of universe. Further, the Λ(t) showed increasing trends while G(t) showed decreasing trends for both cases. Finally, the range −1.99×10−10yr−1≤G˙G≤0 was estimated mathematically, which is similar to the results obtained from observational data.

Observational Constraints on F(T,TG) Gravity with Hubble’s Parametrization

“…The other one is to transform the gravitational sector (Hilbert-Einstein action) instead which resulted in modified gravity theories. An extension of Hilbert-Einstein action leads to the f (R) gravity [13][14][15][16][17][18][19][20][21][22] which represents a class of theories defined as arbitrary functions of R. An approach to transforming the gravitational Hilbert-Einstein action is to spread out the work of the corresponding torsion formulation, called Teleparallel Equivalence of General Relativity (TEGR) [23][24][25][26]. In this class of gravity, the Weitzenbock connection is used instead of the torsion-less Levi-Civita connection and the torsion scalar T can be achieved after the contraction of the torsion tensor.…”

Estimations of the Jensen Gap and Their Applications Based on 6-Convexity

“…Convex functions have many attractive and important properties, and due to these properties and their characteristics, convex functions play a leading role in the solutions to many complicated problems [7][8][9]. Moreover, convex functions are also popular because they deal with problems very smoothly [10][11][12]. Due to this, convex functions have attracted the attention of many researchers [13][14][15].…”