Quantum gravity effects in black holes and cosmology

对于原子或原子核大小的微观现象，众所周知，经典力学不能提供对物理世界的准确描述。目前，对这种小尺度现象的成功描述是由量子力学提供的，这是一个奇怪而令人惊讶的理论，与日常对物质和运动的直觉相去甚远。 为了得到对自然的量子描述，人们首先从牛顿及其继任者发展的那种类型的经典描述开始，并对其应用一种被称为“量子化”的数学过程。到目前为止，在自然界观察到的四种已知作用力中，有三种都是这样做的。这就是电磁力、弱核力和强核力。量子化过程产生了量子理论，然后可以进行测试。有趣的是，这个过程对这三种力都很有效，但对第四种力就不是这样了，这就是引力。 引力之所以不同寻常，部分是因为爱因斯坦将其描述为时空动力学的不同寻常的经典描述，部分是因为量子化过程本身，它需要一个固定的时空，也就是我们所知的“背景”。似乎需要的是一种“独立于背景”的量化过程。 这一提议旨在将这样的量子化应用于量子引力和经典引力交界处的两个重要问题。第一个是黑洞物理学，第二个是宇宙学。第一个项目的目标是探索黑洞辐射的最后阶段，第二个项目的目标是研究宇宙学标准模型的假设如何来自量子引力。

For microscopic phenomena at the scale of the size of atoms or nuclei, it is well established that classical mechanics does not provide an accurate description of the physical world. At present the successful description of such small scale phenomena is provided by quantum mechanics, which is a strange and surprising theory, far removed from everyday intuitions about matter and motion. To arrive at a quantum description of nature, one begins with a classical description of the type developed by Newton and his successors, and applies to it a mathematical procedure called "quantization." This has worked well for three of the four known forces so far observed in nature. These are the electromagnetic, weak and strong nuclear forces. The quantization process produces a quantum theory, which can then be tested. It is an interesting fact that this procedure has worked work well for these three forces, but not for the forth one, which is the gravitational force. The reason why gravity is exceptional is due partly to the unusual classical description of it provided by Einstein as the dynamics of spacetime, and partly to the quantization procedure itself, which requires a fixed spacetime, also known as a "background." What appears to be required is a "background independent" quantization procedure. This proposal aims to apply such a quantization to two important problems that lie at the interface of quantum and classical gravity. The first is black hole physics and the second is cosmology. The goal of the first project is to probe the last stages of black hole radiation, and that of the second is to study how the assumptions of the standard model of cosmology might come from quantum gravity.