论文标题
模糊的多极结构
The multipolar structure of fuzzballs
论文作者
论文摘要
我们扩展并完善一种一般方法，以提取任意固定空间的多极矩，并将其应用于对$ {\ cal n} {\ cal n} {\，= \，} 2 $四维超级强烈重力的研究，将其应用于$ {\ cal n} {\ cal n} {\ cal n} {\ cal n} {\ cal n} {\ cal n} {这些微晶格几何形状可以携带角动量，并且比Kerr黑洞具有丰富的多极结构。特别是它们打破了轴向和赤道对称性，从而产生了大量的非平凡多极矩。在研究了一些分析示例之后，我们通过统计分析探索了该家族的四维参数空间。我们发现，微晶质量和自旋多极矩通常（但并非总是如此），比具有相同质量和角动量的Kerr黑洞的量矩（但并非总是如此）。此外，我们发现数值证据表明，与这些微晶格的（无量纲）矩相关的一些不变剂与微晶体大小单调生长，并在所有中心碰撞时获得的黑洞极限显示了全局最小值。我们的分析与用电磁和重力波探针的深色紧凑物体的多极矩进行测量相关，并进行了观察性测试，以将模糊与古典黑洞区分开。
We extend and refine a general method to extract the multipole moments of arbitrary stationary spacetimes and apply it to the study of a large family of regular horizonless solutions to $ {\cal N}{\,=\,}2$ four-dimensional supergravity coupled to four Abelian gauge fields. These microstate geometries can carry angular momentum and have a much richer multipolar structure than the Kerr black hole. In particular they break the axial and equatorial symmetry, giving rise to a large number of nontrivial multipole moments. After studying some analytical examples, we explore the four-dimensional parameter space of this family with a statistical analysis. We find that microstate mass and spin multipole moments are typically (but not always) larger that those of a Kerr black hole with the same mass and angular momentum. Furthermore, we find numerical evidence that some invariants associated with the (dimensionless) moments of these microstates grow monotonically with the microstate size and display a global minimum at the black-hole limit, obtained when all centers collide. Our analysis is relevant in the context of measurements of the multipole moments of dark compact objects with electromagnetic and gravitational-wave probes, and for observational tests to distinguish fuzzballs from classical black holes.
