Center for Fundamental Physics, University of Maryland, College Park, Maryland 20742-4111, USA.
Phys Rev Lett. 2009 Oct 2;103(14):141101. doi: 10.1103/PhysRevLett.103.141101. Epub 2009 Sep 28.
It has long been known that a maximally spinning black hole cannot be overspun by tossing in a test body. Here we show that if instead the black hole starts out with below maximal spin, then indeed overspinning can be achieved. We find that requirements on the size and internal structure of the test body can be met if the body carries in orbital but not spin angular momentum. Our analysis neglects radiative and self-force effects, which may prevent the overspinning.
长期以来，人们一直知道，一个自旋达到最大值的黑洞不可能通过投入一个测试体来过度旋转。在这里，我们表明，如果黑洞开始时的自旋低于最大值，那么确实可以实现过度旋转。我们发现，如果测试体携带轨道角动量而不是自旋角动量，则可以满足对其大小和内部结构的要求。我们的分析忽略了辐射和自引力效应，这些效应可能会阻止过度旋转。
