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This article explores the impact of bulk viscosity on understanding the universe's accelerated expansion within the context of modified $f(T,\mathcal{T})$ gravity, which is an extension of the $f(T)$ gravitational theory, allowing a broad…

General Relativity and Quantum Cosmology · Physics 2024-07-29 Raja Solanki , Aaqid Bhat , P. K. Sahoo

Bulk viscosity is the only viscous influence that can change the background dynamics in a homogeneous and isotropic universe. In the present work, we analyze the bulk viscous cosmological model with the bulk viscosity coefficient of the…

General Relativity and Quantum Cosmology · Physics 2021-12-13 Gaurav Gadbail , Simran Arora , P. K. Sahoo

We describe the accelerated expansion of the late-time universe using a generalized equation of state (EoS) when account is taken of bulk viscosity. We assume a homogeneous and isotropic Friedmann-Robertson-Walker spacetime. Solutions of…

General Relativity and Quantum Cosmology · Physics 2019-08-05 I. Brevik , A. N. Makarenko , A. V. Timoshkin

Recent studies indicate that, near equilibrium condition could not be maintained for bulk viscous matter models during the accelerated expansion of the universe in the context of Einstein's gravity, without including the cosmological…

General Relativity and Quantum Cosmology · Physics 2023-03-28 Vishnu A Pai , Titus K Mathew

From a phenomenological point of view, we analyze the dynamics of the Universe at late times by introducing a polynomial and hyperbolic bulk viscosity into the Einstein field equations respectively. We constrain their free parameters using…

General Physics · Physics 2019-10-01 A. Hernández-Almada

Since the late 1990's observations of type Ia Supernova, our universe is predicted to experience a late time cosmic acceleration. Theoretical support to this observation were intended to be built via proposition of a hypothetical fluid…

General Relativity and Quantum Cosmology · Physics 2020-08-10 Promila Biswas , Parthajit Roy , Ritabrata Biswas

To recreate the cosmological models, we employed the parametrization approach in modified teleparallel Gauss-Bonnet gravity. It has been interesting to apply the parametrization approach to investigate cosmological models. The real benefit…

General Relativity and Quantum Cosmology · Physics 2022-12-29 Santosh V. Lohakare , B. Mishra , S. K. Maurya , Ksh. Newton Singh

In this paper, we have investigated the late time cosmic acceleration issue in the context of $f(R,T)$ gravity. The matter field is considered to be that of viscous fluid. The model has been framed as a mathematical formalism and the effect…

General Relativity and Quantum Cosmology · Physics 2022-07-19 Sankarsan Tarai , Pratik P Ray , B. Mishra , S. K. Tripathy

In the generalized matter-geometry coupling theory, we investigate the physical characteristics and causality of some new cosmological models for a flat, homogeneous, and isotropic spacetime filled with stiff, radiation, dust, and curvature…

General Relativity and Quantum Cosmology · Physics 2025-04-10 Dinesh Chandra Maurya , Javlon Rayimbaev , Inomjon Ibragimov , Sokhibjan Muminov

In this article, we considered the bulk viscous fluid in the formalism of modified gravity in which the general form of a gravitational action is $f(R, T)$ function, where $R$ is the curvature scalar and $T$ is the trace of the energy…

General Relativity and Quantum Cosmology · Physics 2017-08-02 G. C. Samanta , R. Myrzakulov

In this paper, we study the $f(T,\mathcal{T})$ gravity model in the presence of the bulk viscosity by the flat-FRW metric. The field equation is obtained by teleparallel gravity with tetrad field. The universe components are considered as…

General Relativity and Quantum Cosmology · Physics 2020-12-18 T. Mirzaei-Rezaei , Alireza Amani , E. Yusofi , S. Rouhani , M. A. Ramzanpour

In this paper, we first obtain the energy density by the approach of the new agegraphic dark energy model, and then the $f(T,B)$ gravity model is studied as an alternative to the dark energy in a viscous fluid by flat-FRW background, in…

General Relativity and Quantum Cosmology · Physics 2020-06-17 A. Pourbagher , Alireza Amani

We investigate the hypothesis that the evolution of the Universe can be described by a single dark fluid whose effective equation of state (EoS), $\omega_{\rm{eff}}$, is a linear combination of a logarithmic term and a power law term, both…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-30 Vipin Chandra Dubey , Subhajit Saha , Abdulla Al Mamon

We investigate the cosmological implications of $f(Q,C)$ gravity with $f(Q,C)=\alpha Q+\beta C$, where $Q$ is the non-metricity scalar and $C$ encapsulates cosmological expansion terms. Three parameterizations of the EoS for dark energy,…

General Relativity and Quantum Cosmology · Physics 2024-11-28 Amit Samaddar , S. Surendra Singh

In this paper, the dynamical behavior of the accelerated expansion of the universe is studied within the framework of $f(T)$ gravity by considering a well-motivated functional form of $f(T)$. A specific form of the Hubble parameter is…

General Relativity and Quantum Cosmology · Physics 2026-03-20 Khomesh R. Patle , G. P. Singh

We propose the unified description of the early acceleration (cosmological inflation) and the present epoch of so called "dark energy". The inflation can be described by cosmic fluid with van der Waals equation of state and with viscosity…

General Relativity and Quantum Cosmology · Physics 2022-01-19 A. V. Astashenok , S. D. Odintsov , A. S. Tepliakov

In this paper, we investigate the cosmic expansion scenarios within the framework of $f(Q,T)$ gravity by using the affine equation of state (EoS) parameter. Specifically, we consider the linear form $f(Q,T)=Q+\beta T$, where $\beta$ is a…

General Relativity and Quantum Cosmology · Physics 2026-04-24 Romanshu Garg , G. P. Singh

This study explores the bouncing solutions within the framework of modified $f(Q, L_m)$ gravity. We examine four prominent bouncing models, the symmetric bounce, super bounce, oscillatory bounce, and matter bounce, each of which has been…

General Relativity and Quantum Cosmology · Physics 2026-04-28 S. A. Kadam , V. A. Kshirsagar , Santosh Kumar Yadav

The Hubble constant tension problem is analysed in the framework of a class of modified gravity, the so-called $F(R)$ gravity. To do so, we explore two models: an exponential and a power-law $F(R)$ gravities, which includes an early dark…

General Relativity and Quantum Cosmology · Physics 2021-03-24 Sergei D. Odintsov , Diego Sáez-Chillón Gómez , German S. Sharov

In this paper, we present a comprehensive cosmological analysis within the framework of $f(R, \Sigma, T)$ gravity, a modified theory that incorporates nonlinear matter-geometry coupling via the inclusion of both the trace of the…

General Relativity and Quantum Cosmology · Physics 2025-11-24 S. H. Shekh , N. Myrzakulov , Anil Kumar Yadav , Anirudh Pradhan