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arXiv 0809.2325gr-qc
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改进的Einstein方程约束格式:唯一性问题的一种解决方法

Improved constrained scheme for the Einstein equations: An approach to the uniqueness issue

Isabel Cordero-Carrión, Pablo Cerdá-Durán, Harald Dimmelmeier, José Luis Jaramillo, Jérôme Novak, Eric Gourgoulhon

摘要:

在爱因斯坦方程的约束公式的椭圆扇区中的唯一性问题对一些数值解的物理有效性有着巨大的影响,例如在计算非常紧凑的恒星或新生黑洞的时空时。Bonazzola,Gourgoulhon,Grandclément和Novak提出的完全约束公式(FCF)就是其中之一。它包含,作为一个特殊的情况下,近似的共形平坦性条件(CFC),在过去的十年中,已被用于许多天体物理学的应用。FCF的椭圆部分与CFC格式中的椭圆方程基本上共用相同的微分算子。我们在这里提出了一个重新制定的椭圆部门的CFC的基本属性,克服了当地的唯一性问题。我们的新配方的正确行为是通过一组数值模拟确认。最后,我们将这些想法扩展到自由现金流量,补充在以前的研究中进行的数学分析。

英文摘要:

Uniqueness problems in the elliptic sector of constrained formulations of Einstein equations have a dramatic effect on the physical validity of some numerical solutions, for instance when calculating the spacetime of very compact stars or nascent black holes. The fully constrained formulation (FCF) proposed by Bonazzola, Gourgoulhon, Grandclément, and Novak is one of these formulations. It contains, as a particular case, the approximation of the conformal flatness condition (CFC) which, in the last ten years, has been used in many astrophysical applications. The elliptic part of the FCF basically shares the same differential operators as the elliptic equations in CFC scheme. We present here a reformulation of the elliptic sector of CFC that has the fundamental property of overcoming the local uniqueness problems. The correct behavior of our new formulation is confirmed by means of a battery of numerical simulations. Finally, we extend these ideas to FCF, complementing the mathematical analysis carried out in previous studies.

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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