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Recently, in the context of $f(R)$ modified theories of gravity, a new type of model has been proposed where one directly couples the scalar curvature to matter. As any model in $f(R)$ theory, there are certain conditions which have to be…

General Relativity and Quantum Cosmology · Physics 2015-05-13 Orfeu Bertolami , Miguel Carvalho Sequeira

In this paper, we consider the flat Friedmann Lematre Robertson-Walke metric in the presence of perfect fluid models and extended $f(R,G,T)$ gravity (where $R$ is the Ricci scalar, $G$ is the Gauss Bonnet invariant and $T$ stands for trace…

General Relativity and Quantum Cosmology · Physics 2022-12-21 M. Ilyas , Aftab Ahmad , Fawad Khan , M. Wasif

This review summarizes the current status of the energy conditions in general relativity and quantum field theory. We provide a historical review and a summary of technical results and applications, complemented with a few new derivations…

General Relativity and Quantum Cosmology · Physics 2020-06-08 Eleni-Alexandra Kontou , Ko Sanders

We examine the validity of classical energy conditions in nonsingular bouncing cosmological solutions arising in quadratic curvature gravity minimally coupled to a scalar field. Focusing on the null, weak, strong, and dominant energy…

General Relativity and Quantum Cosmology · Physics 2026-04-30 Yuki Hashimoto , Kazuharu Bamba , Sanjay Mandal

In order to constrain $f(R,L_{m})$ gravity from theoretical aspects, its energy conditions are derived in this paper. These energy conditions given by us are quite general and can be degenerated to the well-known energy conditions in…

General Physics · Physics 2015-06-12 Jun Wang , Kai Liao

We construct the energy conditions for the recently proposed $f(R,L,T)$ gravity theory, for which $f$ is a generic function of the Ricci scalar $R$, matter lagrangian density $L$ and trace of the energy-momentum tensor $T$. We analyse two…

General Relativity and Quantum Cosmology · Physics 2024-06-25 Simran Arora , P. H. R. S. Moraes , P. K. Sahoo

We study the dynamical description of scalar-tensor gravity by performing the best-fit analysis for two cases of exponential and power-law form of the potential and scalar field function coupled to the curvature. The models are then tested…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Hossein Farajollahi , Amin Salehi , Mohammad Nasiri

Attention has been recently called upon the fact that the weak and null energy conditions and the second law of thermodynamics are violated in wormhole solutions of Einstein's theory with classical, nonminimally coupled, scalar fields as…

High Energy Physics - Theory · Physics 2009-11-07 S. Bellucci , V. Faraoni

We consider generalized teleparallel gravity in the flat FRW universe with a viable power-law f(T) model. We construct its equation of state and deceleration parameters which give accelerated expansion of the universe in quintessence era…

General Physics · Physics 2015-06-18 M. Sharif , Shamaila Rani

The energy conditions and the Dolgov-Kawasaki criterion in generalized $f(R)$ gravity with arbitrary coupling between matter and geometry are derived in this paper, which are quite general and can degenerate to the well-known energy…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Jun Wang , Ya-Bo Wu , Yong-Xin Guo , Wei-Qiang Yang , Lei Wang

In general relativity, the energy conditions are invoked to restrict general energy-momentum tensors on physical grounds. We show that in the standard Friedmann-Lemaitre-Robertson-Walker approach to cosmological modelling where the equation…

Astrophysics · Physics 2009-11-11 J. Santos , J. S. Alcaniz , M. J. Reboucas

The concept of energy lies at the foundation of physical science. In general relativity and quantum field theory, the positivity and conservation of energy are encapsulated by the so-called energy-momentum tensor and the energy conditions.…

High Energy Physics - Theory · Physics 2025-12-02 Norihiro Iizuka , Akihiro Ishibashi , Kengo Maeda , Haruki Nakayama , Tatsuma Nishioka

In today's scenario, going beyond Einstein's theory of gravity leads us to some more complete and modified gravity theories. One of them is the $f(R,T)$ gravity in which $ R $ is the Ricci scalar, and $ T $ is the trace of the…

General Relativity and Quantum Cosmology · Physics 2022-01-04 P. K. Sahoo , Sanjay Mandal , Simran Arora

$f(P)$ 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 \cite{p}. The present…

General Relativity and Quantum Cosmology · Physics 2022-03-29 Snehasish Bhattacharjee

In the standard Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmological model, the energy conditions provides model-independent bounds on the behavior of the distance modulus. However, this method can not provide us the detailed information…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-20 Wen-Fei Liu , Jing Niu , Juan Li , Tong-Jie Zhang

The present study is motivated by the study of reference [1], where the generalized second law of thermodynamics has been investigated for a flat FRW universe for two viable models of $f(T)$ gravity. In the present work, we have considered…

General Relativity and Quantum Cosmology · Physics 2013-11-22 Rahul Ghosh , Antonio Pasqua , Surajit Chattopadhyay

We consider $f(R, T)$ theory of gravity, where $R$ is the curvature scalar and $T$ the trace of the energy momentum tensor. Attention is attached to the special case, $f(R, T)= R+2f(T)$ and two expressions are assumed for the function…

General Relativity and Quantum Cosmology · Physics 2015-06-05 F. G. Alvarenga , M. J. S. Houndjo , A. V. Monwanou , Jean B. Chabi Orou

We are experiencing a golden age of experimental cosmology, with exact and accurate observations being used to constrain various gravitational theories like never before. Alongside these advancements, energy conditions play a crucial…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-08 Y. Myrzakulov , O. Donmez , M. Koussour , S. Muminov , D. Ostemir , J. Rayimbaev

This paper studies the viable regions of some cosmic models in a higher derivative $f(R,\square R, T)$ theory with the help of energy conditions (where $R$ and $T$ are the Ricci scalar, and trace of energy momentum tensor, respectively).…

General Relativity and Quantum Cosmology · Physics 2020-03-03 M. Ilyas , Z. Yousaf , M. Z. Bhatti

We study and derive the energy conditions in generalized non-local gravity, which is the modified theory of general relativity (GR) obtained by adding a term $m^{2n-2}R\Box^{-n}R$ to the Einstein-Hilbert action. Moreover, in order to get…

General Relativity and Quantum Cosmology · Physics 2017-08-02 Ya-Bo Wu , Xue Zhang , Bo-Hai Chen , Nan Zhang , Meng-Meng Wu