Echoes from corpuscular black holes
Echoes from corpuscular black holes
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DOI：
10.1088/1475-7516/2020/12/041
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发表时间：
2020-05
影响因子：
6.4
通讯作者：
L. Buoninfante
中科院分区：
文献类型：
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作者：
L. Buoninfante
在黑洞的微粒图像中，不存在视界的几何概念，相反，视界只出现在半经典极限中。因此，很自然地会问，如果我们向微粒黑洞发送信号会发生什么？我们证明了在视界尺度下的量子效应意味着存在一个位于有效半径R=Rs（1+ N）的表面，该半径略大于Schwarzschild半径Rs，其中N =1/N，N是组成系统的引力子数。因此，物体的反射率可以是非零的，事实上，我们发现能量与霍金温度相当的入射波可以有一阶后向散射的概率。因此，模式可以被捕获在位于光子球和粒子黑洞表面的两个势垒之间，并且可以产生周期性的回波。回波的时间延迟结果是与加扰时间相同的数量级，即，以普朗克长度为单位，它的读数是N log N。我们还表明，粒子黑洞的量子参数，或者换句话说，紧凑性，与量子耦合，测量引力子之间的相互作用强度相一致，并讨论了这一显着的功能的物理含义。
In the corpuscular picture of black hole there exists no geometric notion of horizon which, instead, only emerges in the semi-classical limit. Therefore, it is very natural to ask—what happens if we send a signal towards a corpuscular black hole? We show that quantum effects at the horizon scale imply the existence of a surface located at an effective radius R=Rs(1+ϵ) slightly larger than the Schwarzschild radius Rs, where ϵ=1/N and N is the number of gravitons composing the system. Consequently, the reflectivity of the object can be non-zero and, indeed, we find that incoming waves with energies comparable to the Hawking temperature can have a probability of backscattering of order one. Thus, modes can be trapped between the two potential barriers located at the photon sphere and at the surface of a corpuscular black hole, and periodic echoes can be produced. The time delay of echoes turns out to be of the same order of the scrambling time, i.e., in units of Planck length it reads √N log N. We also show that the ϵ-parameter, or in other words the compactness, of a corpuscular black hole coincides with the quantum coupling that measures the interaction strength among gravitons, and discuss the physical implications of this remarkable feature.