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arXiv 1201.4989gr-qcastro-ph.SRhep-th
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关于物质-引力耦合范式的新见解

New insights on the matter-gravity coupling paradigm

Térence Delsate, Jan Steinhoff

摘要:

广义相对论中物质与引力的耦合是由应力张量与几何之间的比例关系给出的。这是一个定向假设,由应力张量和爱因斯坦张量都是无发散的这一事实驱动。但广义相对论本质上是一种非线性理论,因此没有明显的理由说明与物质的耦合应该是线性的。另一方面,修正的引力理论通常会影响真空动力学,但保持与物质的耦合是线性的。在这封信中,我们解决了一致的非线性引力/物质耦合的影响。最近由Banados和Ferreira引入的Eddington启发的Born-Infeld理论提供了这种耦合修改的启发性实现。我们发现,这个理论耦合到一个完美的流体减少到广义相对论耦合到一个非线性修改的完美流体,导致修改后的耦合和修改状态方程之间的模糊性。我们讨论了这种简并性的观测结果,并认为这样一个完整的广义相对论是可行的,从实验和理论的角度来看,通过能量条件,一致性和奇异性避免的角度。我们使用这些结果来讨论改变耦合模式的影响。

英文摘要:

The coupling between matter and gravity in General Relativity is given by a proportionality relation between the stress tensor and the geometry. This is an oriented assumption driven by the fact that both the stress tensor and the Einstein tensor are divergenceless. However, General Relativity is in essence a nonlinear theory, so there is no obvious reason why the coupling to matter should be linear. On another hand, modified theories of gravity usually affect the vacuum dynamics, yet keep the coupling to matter linear. In this Letter we address the implications of consistent nonlinear gravity/matter coupling. The Eddington inspired Born-Infeld theory recently introduced by Banados and Ferreira provides an enlightening realization of such coupling modifications. We find that this theory coupled to a perfect fluid reduces to General Relativity coupled to a nonlinearly modified perfect fluid, leading to an ambiguity between modified coupling and modified equation of state. We discuss observational consequences of this degeneracy and argue that such a completion of General Relativity is viable from both an experimental and theoretical point of view through energy conditions, consistency, and singularity-avoidance perspectives. We use these results to discuss the impact of changing the coupling paradigm.

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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