论文标题
空刺激性焦点，封闭的无效曲线和超渗透
Null Hypersurface Caustics, Closed Null Curves, and Super-Entropy
论文作者
论文摘要
最近发现，与通常的Kerr-Ads案相反，无效的超曲面可以在超级渗透的Kerr-Ads黑洞的事件视野之外发展苛刻。在这项工作中，我们探讨了其他一些黑洞空位的例子，其中这种外部苛性剂可以发展出来。如果存在封闭的无效曲线，例如，在taub-nut和“ transunital” kerr-ads空间时，则它与最小分离参数的无效的速率（NHC）相吻合。因此，在形成封闭时间曲线的边缘的时空可能会发展出苛性速度。超级渗透黑洞的已知示例也具有外部NHC，尽管这种空间不含封闭的空/及时曲线。然而，封闭的因果曲线，NHC和超脑膜之间的关系并不直接。最好用BTZ黑色字符串来说明这一点，对于额外的尺寸和电荷值的某些选择，可以是超级渗透的。但是，即使那些不是超级渗透的人也可以在地平线外接纳NHC。
Recently it was discovered that null hypersurfaces can develop caustics outside the event horizon of super-entropic Kerr-AdS black holes, in contrast to the usual Kerr-AdS case. In this work we explore a few more examples of black hole spacetimes in which such exterior caustics can develop. If a closed null curve is present, e.g., in the case of Taub-NUT and the "transunital" Kerr-AdS spacetimes, then it coincides with a null hypersurface caustic (NHC) of a minimal separation parameter. Thus a spacetime on the verge of forming closed timelike curves could develop a caustic. Known examples of super-entropic black holes also have exterior NHC, although such spacetimes are free of closed null/timelike curves. Nevertheless the relationship between closed causal curves, NHC, and super-entropy is not straightforward. This is best illustrated with the BTZ black string, which for some choices of the warp factor in the extra dimension and the value of the charge, can be super-entropic. However, even those that are not super-entropic can admit NHC outside the horizon.
