Clocking Out Superradiance Limits

X（3872）电磁辐射衰变中的超辐射和亚辐射

Superradiance and subradiance in the electromagnetic radiative decay of X(3872)

指出如果最近观测到的X（3872）共振的分子解释是正确的，那么大自然可能已经为我们研究Dicke的超辐射和亚辐射现象准备了一个很好的实验室。计算了X（3872）的超辐射和超辐射因子，讨论了超辐射因子对X（3872）电磁辐射衰减的影响。我们的结果使用坐标空间表示是类似的Voloshin的动量空间的结果。

Black hole superradiance of self-interacting scalar fields

Black hole superradiance is a powerful probe of light, weakly-coupled hidden sector particles. Many candidate particles, such as axions, generically have self-interactions that can influence the evolution of the superradiant instability. As pointed out in arXiv:1604.06422 in the context of a toy model, much of the existing literature on spin-0 superradiance does not take into account the most important self-interaction-induced processes. These processes lead to energy exchange between quasi-bound levels and particle emission to infinity; for large self-couplings, superradiant growth is saturat…

The Penrose process, superradiance and ergoregion instabilities

Superradiant scattering is a radiation enhancement process that takes place in many contexts, and which has recently found exciting applications in astro and particle physics. In the framework of curved spacetime physics, it has been associated with the classical Penrose process for particles. Superradiance is usually also associated with bosonic fields around geometries with ergoregions and horizons. These notions are in clear tension however: the Penrose process occurs for horizonless geometries, and particles are composed of fermions. Here, we resolve the tension in its different aspects, b…

从黑洞喷流中获得更多：一种统计严谨的方法用于通过黑洞自转测量约束超轻玻色子

Getting More Out of Black Hole Superradiance: a Statistically Rigorous Approach to Ultralight Boson Constraints from Black Hole Spin Measurements

本文提出一种统计严谨的方法，利用黑洞自转测量约束超轻玻色子的质量和相互作用，改进现有ULB约束并影响QCD轴子研究。

Superradiance in massive vector fields with spatially varying mass

Superradiance is a process by which massive bosonic particles can extract energy from spinning black holes, leading to the build up of a "cloud" if the particle has a Compton wavelength comparable to the black hole's Schwarzschild radius. One interesting possibility is that superradiance may occur for photons in a diffuse plasma, where they gain a small effective mass. Studies of the spin-0 case have indicated that such a build up is suppressed by a spatially varying effective mass, supposed to mimic the photons' interaction with a physically realistic plasma density profile. We carry out rela…

Superradiance evolution of black hole shadows revisited

Black hole (BH) shadows can be used to probe new physics in the form of ultra-light particles via the phenomenon of superradiant instability. By directly affecting the BH mass and spin, superradiance can lead to a time evolution of the BH shadow, which nonetheless has been argued to be unobservable through Very Long Baseline Interferometry (VLBI) over realistic observation timescales. We revisit the superradiance-induced BH shadow evolution including the competing effects of gas accretion and gravitational wave (GW) emission and, as a first step towards modelling realistic new physics scenario…