Black holes and cosmology in quantum gravity

“量子引力”一词被用来描述将量子力学的思想应用于引力理论的任何尝试。这一研究领域源于一种被广泛接受的观点，即基本粒子等小尺度物体的物理是用量子理论来描述的，引力也应该是如此。人们很好地理解了大尺度上的引力，如太阳系和其他地方；牛顿的理论非常接近我们所看到的，但已经被爱因斯坦的广义相对论所取代。这一理论预测了新的效应，比如光被引力弯曲，并得到了实验验证。然而，爱因斯坦的理论在极端情况下是不成立的，比如大质量恒星的引力坍塌，或者我们的宇宙开始猛烈地开始。在这两种情况下，物理的未知性质在很小的距离都变得重要起来。目前，只有一部分是量子的不完全混合理论是可用的。它预测黑洞会发出辐射，并最终变得比基本粒子的大小更小。在某种程度上，它还以一种似乎与早期量子引力时代脱节的方式描述了我们现在宇宙的状态。我的研究计划的目标是提出一些想法，让我们能够更深入地理解引力的量子本质，因为它适用于非常早期的宇宙，以及黑洞演化的非常后期阶段。我提出的框架是一个可以用计算机模拟描述物质和几何构型的量子态的演化的框架。

The term "Quantum gravity" is used to describe any attempt at a theory that applies ideas from quantum mechanics to gravitation. This research area has its origins in the widely accepted view that the physics of small scale objects, such as elementary particles, is described by quantum theory, and that the same should be true for gravity.   Gravitation on large scales, such as the solar system and beyond, is well understood; Newton's theory is a very good approximation to what we see, but has been superseded by Einstein's general relativity. This theory has predicted new effects, such as the bending of light by gravity, that are experimentally verified.  However, Einstein's theory fails  in extreme situations, such as the gravitational collapse of a massive star, or the violent beginning of our universe. In both instances the unknown properties of physics at very small distances become important. At present an incomplete hybrid theory that is only part quantum is available. It predicts that black holes emit radiation, and eventually become smaller than the size of elementary particles. To an extent it also describes the state of our present universe in a way that appears disconnected from its very early quantum gravity era. The goal of my research program is to develop ideas that will allow a deeper understanding of the quantum nature of gravity as it applies to the very early universe, and the very late stages of black hole evolution. The framework I propose is one in which it is possible to simulate using a computer the evolution of quantum states describing configurations of matter and geometry.