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arXiv 1409.3018gr-qcastro-ph.HE
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用带电粒子摧毁近极值克尔黑洞:测试磁场能作为宇宙审查器吗?

Destroying a near-extremal Kerr black hole with a charged particle: Can a test magnetic field serve as a cosmic censor?

Sanjar Shaymatov, Mandar Patil, Bobomurat Ahmedov, Pankaj S. Joshi

摘要:

研究了带电测试粒子在测试磁场作用下对近极值Kerr黑洞破坏过程的影响。研究表明,将带电测试粒子投入近极值旋转的黑洞中,使其通过极值,即使Kerr黑洞变为Kerr-Newmann裸奇点是可能的。通常在天体物理学的场景中,黑洞被认为是被磁场包围着。磁场虽然很小,但由于电磁力比重力强得多,因此洛伦兹力很大,对带电粒子的运动产生了巨大的影响。因此,测试磁场可以影响摧毁黑洞的过程,并恢复天体物理学背景下的宇宙审查。我们表明,一个测试磁场将作为一个宇宙审查超过一定的阈值。我们试图通过比较能量密度和测试粒子引起的曲率变化来测量磁场的大小。我们发现,所需的磁场仅与其背景几何效应与测试粒子的微小反作用相当的值一样强或稍强。然而,在这种情况下,必须考虑背景几何上的磁场的影响,这在没有任何精确的近极值旋转磁化黑洞解的情况下是难以实现的。我们认为,磁场仍将作为宇宙审查员。

英文摘要:

We investigate effect of a test magnetic field on the process of destroying near-extremal Kerr black hole with a charged test particle. It has been shown that it would be possible to throw a charged test particle into the near extremal rotating black hole and make it go past the extremality i.e. turn Kerr black hole into the Kerr-Newmann naked singularity. Typically in an astrophysical scenario black holes are believed to be surrounded by a magnetic field. Magnetic field although small, affects motion of charged particles drastically due to the large Lorentz force, as the electromagnetic force is much stronger that the gravity. Thus a test magnetic field can affect the process of destroying black holes and restore the cosmic censorship in the astrophysical context. We show that a test magnetic field would act as a cosmic censor beyond a certain threshold value. We try to gauge the magnitude of the magnetic field by comparing its energy density with that of the change in the curvature induced by the test particle. We find that the magnetic field required in only as strong as or slightly stronger as compared to the value for which its effect of the background geometry is comparable to the tiny backreaction as that of the test particle. In such a case however one has to take take into account effect of the magnetic field on the background geometry, which is difficult to implement in the absence of any exact near-extremal rotating magnetized black hole solutions. We argue that magnetic field would still act as a cosmic censor.

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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