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arXiv 1212.0551gr-qcastro-ph.COhep-phhep-th
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天体物理系统中的超辐射不稳定性

Superradiant instabilities in astrophysical systems

Helvi Witek, Vitor Cardoso, Akihiro Ishibashi, Ulrich Sperhake

摘要:

轻玻色子自由度已经成为暗物质的重要候选者。这些场在弯曲时空周围的演化还知之甚少,但预计会显示出有趣的效应。特别是,光玻色子场与大多数星系中的关键角色--超大质量黑洞的相互作用,可以提供超辐射和非线性玻色诺瓦式坍缩的丰富多彩的例子。反过来,对旋转黑洞的观测有望对我们宇宙中假定的大质量玻色子场的质量施加严格的限制。本文的目的是对旋转黑洞附近线性化质量标量场和矢量场的演化进行全面的研究。对于一定的玻色子场质量范围,场可以被困在视界外的势垒中并过渡到束缚态。因为存在许多这样的准束缚态,所以一般的结果是调幅正弦或拍频信号。我们认为,这种殴打的出现在过去没有被注意到,事实上被误认为是指数增长。信号的幅度调制强烈地依赖于泛音的相对激发,而泛音的相对激发又与束缚态的地理位置密切相关。我们第一次探讨了大规模的矢量场在一般BH背景下,这是很难,如果不是不可能的,在克尔背景下分离。我们的结果表明,自旋黑洞一般是强烈不稳定的大规模向量场。

英文摘要:

Light bosonic degrees of freedom have become a serious candidate for dark matter. The evolution of these fields around curved spacetimes is poorly understood but is expected to display interesting effects. In particular, the interaction of light bosonic fields with supermassive black holes, key players in most galaxies, could provide colourful examples of superradiance and nonlinear bosenova-like collapse. In turn, the observation of spinning black holes is expected to impose stringent bounds on the mass of putative massive bosonic fields in our universe. Our purpose here is to present a comprehensive study of the evolution of linearized massive scalar and vector fields in the vicinities of rotating black holes. For a certain boson field mass range, the field can become trapped in a potential barrier outside the horizon and transition to a bound state. Because there are a number of such quasi-bound states, the generic outcome is an amplitude modulated sinusoidal, or beating, signal. We believe that the appearance of such beatings has gone unnoticed in the past, and in fact mistaken for exponential growth. The amplitude modulation of the signal depends strongly on the relative excitation of the overtones, which in turn is strongly tied to the bound-state geography. For the first time we explore massive vector fields in generic BH background which are hard, if not impossible, to separate in the Kerr background. Our results show that spinning BHs are generically strongly unstable against massive vector fields.

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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