arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2003.03720gr-qc
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修正$f(R,T)$引力理论中的一个引力解耦MGD模型

A gravitational decoupling MGD model in modified $f(R,T)$ gravity theory

S. K. Maurya, Abdelghani Errehymy, Ksh. Newton Singh, Francisco Tello-Ortiz, Mohammed Daoud

摘要:

本文研究了在修正的f(R,T)引力理论下,利用最小几何变形(MGD)方法,通过引力退耦,得到描述各向异性物质分布的超致密致密球形系统的恒星内部结构的可能性.根据这一理论,应力-能量张量的协变发散不为零,因此经典粒子的运动不遵循测地线,导致额外的加速度,这足以满足宇宙的晚期加速度,而无需采用奇异物质场。在这方面,我们考虑了代数函数f(R,{ \rm T})= R+2 × T,相应的有效应力-能量张量是守恒的,并导出了精确解,其中$χ$表示一个耦合常数.此外,与新的解决方案相关的物理量从物理和数学的角度来看表现良好,以及没有几何奇点,违反因果关系条件,非减热力学函数。此后,所获得的模型的物理可行性是肯定的,通过执行几个物理测试的主要显着特征,如能量密度,径向和切向压力,各向异性效应,动态平衡,能量条件,和动态稳定性。另一方面,我们在GR,GR+MGD,f(R,T)和f(R,T)+MGD四种不同的情况下,通过改变引力退耦常数α和耦合常数χ作为自由参数,得到了M-R曲线,并发现了这四种情况下的许多致密球形天体的完美拟合。本文的研究表明,用MGD方法通过引力解耦得到的修正的f(R,T)引力是一个适合于解释致密恒星球系统的理论。

英文摘要:

The present paper is devoted to investigating the possibility of getting stellar interiors for ultra-dense compact spherical systems portraying an anisotropic matter distribution employing the gravitational decoupling by means of Minimal Geometric Deformation (MGD) procedure within the modified theory of f(R,T) gravity. According to this theory, the covariant divergence of stress-energy tensor does not vanish, hence the movement of classical particles does not follow geodesics resulting in an extra acceleration which suffices the late-time acceleration of the universe without adopting to exotic matter fields. In this regard, we have considered the algebraic function as f(R, {\rm T})= R+2χT, the corresponding effective stress-energy tensor is conserved as well as the exact solutions are derived, where $χ$ indicates a coupling constant. Moreover, the physical quantities associated with the new solutions are well-behaved from the physical and mathematical point of view as well as free of geometrical singularities, violation of the causality condition, non-decreasing thermodynamic functions. Thereafter, the physical viability of the obtained model is affirmed by performing several physical tests of the main salient features such as energy density, radial, and tangential pressure, anisotropy effect, dynamical equilibrium, energy conditions, and dynamical stability. On the other hand, we have generated the M-R curves from our solutions in the four different scenarios, including GR, GR+MGD, f(R,T) and f(R,T)+MGD, and we found a perfect fit for many compact spherical objects in these scenarios by changing the gravitational decoupling constant αand the coupling constant χas free parameters. The present study reveals that the modified f(R,T) gravity through gravitational decoupling by means of MGD method is a suitable theory to explain compact stellar spherical systems....

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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