Black Hole Superradiance in Rotating Fluids (SURF)

一些最基本的，也许是奇怪的过程预计发生在黑洞附近的观测范围之外。为了解决这个问题，我们利用模拟系统，我们研究在实验中再现一个有效的黑洞的背景流的波动。在文献中，这一研究方向被称为重力模拟模型，或简称为模拟重力。Anaerobic模型不仅提供了一个理论框架，而且还提供了一个实验框架，以验证暴露于“极端”时空几何（如快速旋转的黑洞）的经典和量子场的预测。该项目汇集了模拟重力领域的两位世界公认的专家，旨在将该领域推向一个新的方向：我们提出了开创性的研究，以模拟广义相对论中旋转黑洞附近发生的一些奇异过程以及水和光学系统中的旋转流体。特别是，我们将从理论和实验两方面研究输入波和旋转黑洞时空几何之间的相互作用，这里由旋转流体重新创建。这使我们能够模拟与旋转的黑锄头相关的散射过程，称为超辐射散射。从历史的角度来看，这种辐射是霍金辐射的先驱。更准确地说，黑洞超辐射是来自旋转黑洞的波的散射：如果入射波也具有少量的角动量，它将以增加的振幅被反射，即它以黑洞为代价被放大，从而失去了一些旋转能量。也有人指出，相同的物理现象可能发生在非常不同的系统中，例如，入射到旋转金属（或吸收）圆柱体上的光也可能在反射时被放大。然而，还没有人尝试过实验研究广义相对论之外的基础物理，并与各种流体动力学和旋转系统相关。我们的目标是在两个不同的流体动力学系统中提供有史以来第一个有趣的和基本的放大机制的实验证据。第一个是喷水口，控制，以便获得正确的边界条件，并优化观察BH-SS。第二种是一种不太传统的流体，它是由光制成的。光在特殊介质中的传播可以表现为流体甚至超流体。通过建立在高度发达的光子技术上，例如用于控制和测量激光束波前，我们将实施非常精确的定制和表征实验。该项目的独特之处之一是两个非常不同的实验室系统之间的结合，一个使用水，另一个使用光，以解决与天体物理学，流体动力学和光学系统相关的物理学中的一个突出问题。

Some of the most fundamental and perhaps bizarre processes expected to occur in the vicinity of black holes are out of observational reach. To address this issue we utilise analogue systems where we study fluctuations on a background flow that in the experiment reproduces an effective black hole. In the literature this line of research is referred to as analogue models for gravity, or simply analogue gravity. Analogue models provide not only a theoretical but also an experimental framework in which to verify predictions of classical and quantum fields exposed to 'extreme' spacetime geometries, such as rapidly rotating black holes. This project brings together two world-wide recognised experts in the field of analogue gravity with the aim of pushing the field in a new direction: we propose ground-breaking studies to mimic some of the bizarre processes occurring in the vicinity of rotating black holes from general relativity and rotating fluids in both water and optical systems. In particular, we will investigate both theoretically and experimentally the interaction between an input wave and a rotating black hole spacetime geometry, here recreated by the rotating fluid. This allows us to mimic a scattering process associated to rotating black hoes called superradiant scattering. From a historical viewpoint this kind of radiation is the precursor to Hawking radiation. More precisely, black hole superradiance is the scattering of waves from a rotating black hole: if the incoming wave also possesses a small amount of angular momentum, it will be reflected with an increased amplitude, i.e. it is amplified at the expense of the black hole that thus loses some of its rotational energy. It has also been pointed out that the same physics may take place in very different systems, for example light incident on a rotating metallic (or absorbing) cylinder may also be amplified upon reflection. Yet, no-one has ever attempted to experimentally investigate the underlying physics that extend beyond general relativity and are relevant to a variety of hydrodynamical and rotating systems.We aim to provide the first ever experimental evidence of this intriguing and fundamental amplification mechanism in two different hydrodynamical systems. The first is a water spout, controlled so that the correct boundary conditions are obtained and optimised for observing BH-SS. The second is a less conventional fluid that is made out of light. Light propagating in a special medium can behave as a fluid or even a superfluid. By building upon highly developed photonic technologies e.g. for the control and measurements of laser beam wavefronts, we will implement very precisely tailored and characterised experiments. One of the unique aspects of this project is the marriage between two very different lab-based systems, one using water the other using light, to tackle an outstanding problem in physics that is of relevance to astrophysics, hydrodynamic and optical systems.