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arXiv 2511.13086gr-qchep-th
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高维黑洞中最内稳定圆轨道的无界半径

Unbounded Radius of Innermost Stable Circular Orbit in Higher-Dimensional Black Holes

Hocheol Lee, Bogeun Gwak

AI总结:

本文针对带各向异性能量-动量张量的高维静态球对称渐近平坦黑洞,通过类时测地线有效势分析证明其ISCO半径普遍无界,维度≥8时ISCO可能不存在,揭示了高维与四维黑洞动力学的本质差异。

摘要:

最内稳定圆轨道(ISCO)为时空结构提供了基础检验手段,然而在受各向异性能量-动量张量影响的高维黑洞中,其性质尚未得到充分研究。本研究针对存在各向异性能量-动量张量的高维静态球对称渐近平坦黑洞时空,探究了ISCO的上界问题。研究假设该能量-动量张量满足弱能量条件、迹非正,且满足径向与切向压强约束,上述条件共同等价于带附加约束的主能量条件。通过分析类时测地线的有效势并施加ISCO条件,我们证明高维时空中ISCO半径普遍不存在上界:当维度大于等于8时,ISCO可能不存在,具体取决于能量-动量张量的径向与切向分量;若ISCO存在,其半径是无界的。上述发现推进了我们对高维引力系统轨道稳定性的认知,凸显了高维黑洞动力学与四维黑洞动力学的本质差异。

英文摘要:

The innermost stable circular orbit (ISCO) offers a fundamental test of spacetime structure. However, its behavior in higher-dimensional black holes influenced by anisotropic energy-momentum tensors remains insufficiently explored. In this work, we investigate the upper bound of the ISCO in higher-dimensional, static, spherically symmetric, and asymptotically flat black hole spacetimes in the presence of an anisotropic energy-momentum tensor. The energy-momentum tensor is assumed to satisfy the weak energy condition, possess a non-positive trace, and obey constraints on radial and tangential pressures, collectively equivalent to the dominant energy condition with additional constraints. By analyzing the effective potential for timelike geodesics and imposing ISCO conditions, we demonstrate the general absence of an upper bound on the ISCO radius in higher-dimensional spacetimes. For dimensions greater than or equal to eight, an ISCO may not exist, depending on the radial and tangential components of the energy-momentum tensor. If an ISCO exists, its radius remains unbounded. These findings advance our understanding of orbital stability in higher-dimensional gravitational systems and highlight fundamental differences from four-dimensional black hole dynamics.

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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