We give a survey of the present status of the microstate geometries called superstrata. Superstrata are smooth, horizonless solutions of six-dimensional supergravity that represent some of the microstates of the D1–D5–P black hole in string theory. They are the most general microstate geometries of that sort whose CFT dual states are identified. After reviewing relevant features of the dual CFT, we discuss the construction of superstratum solutions in supergravity, based on the linear structure of the BPS equations. We also review some of recent work on generalizations of superstrata and physical properties of superstrata. Although the number of superstrata constructed so far is not enough to account for the black-hole entropy, they give us valuable insights into the microscopic physics of black holes.

中文翻译：

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超地层

我们对称为超地层的微观几何体的现状进行了调查。Superstrata 是六维超引力的平滑、无视界解，代表弦理论中 D1-D5-P 黑洞的一些微观状态。它们是确定 CFT 双态的那种最通用的微观几何结构。在回顾了对偶 CFT 的相关特征之后，我们讨论了基于 BPS 方程的线性结构的超重力中上层解的构造。我们还回顾了最近关于上层泛化和上层物理特性的一些工作。尽管迄今为止构建的超地层数量不足以解释黑洞熵，但它们为我们提供了对黑洞微观物理学的宝贵见解。