Black holes and their boundaries: from equilibrium properties to how dynamical black holes interact with their environment

黑洞及其边界：从平衡特性到动态黑洞如何与其环境相互作用

• 批准号: 261429-2013
• 负责人: Booth, Ivan
• 金额: $ 3.21万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=633351
• 关键词: Black; holes; their; boundaries; equilibrium

As the moon orbits the Earth, its gravitational field raises the tides. As the tidal bulges flow around the globe, friction between the water and land slows the Earth's rotation. At the same time, the gravitational field of the bulges pulls back on the moon and so terran rotational angular momentum is transformed into lunar orbital angular momentum. As in any problem involving friction, energy is dissipated and a net effect of this gravitational coupling is that the moon recedes from the Earth at a rate of almost 4cm/year. This process nicely demonstrates how we reason in classical physics. The geometry (in this case the shape of the tidal bulge and orbital distance to the moon) interacts with the gravitational field and drives a transfer of energy and angular momentum around the system. Once we know about the forces and the flows of energy and momentum, we feel that we understand the system. Interactions involving black holes are a lot more complicated. By definition, black hole physics involves incredibly strong gravitational fields. Then the gravitational fields of Newtonian physics are replaced by the spacetime geometry of general relativity and no longer superpose in a simple way. Furthermore, close to the black hole we can no longer rely on energy and momentum to build intuition: their conservation laws come from symmetries that no longer exist. To make matters even more confusing, there is not even universal agreement on how to define the boundary of a dynamical black hole. The foundations of classical physical reasoning appear to be lost. A primary focus of this research program will be the study of dynamic black holes and how they interact with their enviroment. In many circumstances, including most astrophysical processes, things are not as dire as they might first appear and many aspects of classical reasoning can be recovered - though with interesting and unexpected twists. I will develop mathematical tools to aid in the understanding of real astrophysical events as well as some more esoteric problems involving higher dimensions, unexpected dualities and other exotica.

当月亮绕地球绕着地球绕，其引力场升起了潮流。随着潮汐凸起的地球群的流动，水和陆地之间的摩擦减慢了地球的旋转。同时，凸起的引力场将其拉回月球上，因此将人旋转角动量转化为月球轨道角动量。与任何涉及摩擦的问题一样，能量会消散，并且这种引力耦合的净效应是，月亮以近4厘米/年的速度从地球退出。这个过程很好地证明了我们在古典物理学中的推理方式。几何形状（在这种情况下，潮汐凸起的形状和向月球的轨道距离的形状）与重力场相互作用，并驱动系统周围的能量和角动量的传递。一旦我们了解了能量和动力的力量和动力的流动，我们就会感到我们了解系统。涉及黑洞的互动要复杂得多。从定义上讲，黑洞物理涉及极强的引力场。然后，牛顿物理学的引力场被一般相对论的时空几何形状取代，而不再以简单的方式超级斑点。此外，靠近我们不再依靠能量和动力来建立直觉的黑洞附近：它们的保护定律来自不再存在的对称性。为了使问题更加令人困惑，甚至没有关于如何定义动态黑洞边界的普遍共识。古典物理推理的基础似乎丢失了。该研究计划的主要重点是研究动态黑洞以及它们如何与环境相互作用。在许多情况下，包括大多数天体物理过程，事物并不像最初出现的那样可怕，并且可以恢复经典推理的许多方面 - 尽管有有趣且出乎意料的曲折。我将开发数学工具，以帮助理解真实的天体物理事件，以及一些更深奥的问题，涉及更高的维度，意外的二元性和其他外来。