Carlip Steven
Department of Physics, University of California, Davis, CA 95616 USA.
Living Rev Relativ. 2005;8(1):1. doi: 10.12942/lrr-2005-1. Epub 2005 Jan 24.
In three spacetime dimensions, general relativity drastically simplifies, becoming a "topological" theory with no propagating local degrees of freedom. Nevertheless, many of the difficult conceptual problems of quantizing gravity are still present. In this review, I summarize the rather large body of work that has gone towards quantizing (2 + 1)-dimensional vacuum gravity in the setting of a spatially closed universe.
在三个时空维度中，广义相对论极大地简化，成为一种没有传播局部自由度的“拓扑”理论。然而，量子化引力的许多困难概念问题仍然存在。在这篇综述中，我总结了在空间封闭宇宙的背景下对（2 + 1）维真空引力进行量子化的相当大量的工作。
