标题： 圈量子引力的对称性约化 显示英文标题

标题： Symmetry Reduction of Loop Quantum Gravity

摘要： 圈量子宇宙学与全圈量子引力之间的关系在第一个非平凡步骤处就失败了：由于拓扑障碍，圈量子宇宙学的构型空间不能嵌入到全圈量子引力的构型空间中。 我们详细研究了这个障碍，因为许多拓扑障碍是物理效应的根源。 为此，我们推导了圈量子引力构型空间的大类子空间的拓扑结构。 这使我们能够找到标准圈量子宇宙学构型空间的扩展，该扩展允许与Fleischhack:2010一致的嵌入。 然后我们构建了平直FRW圈量子宇宙学的嵌入，并发现它渐近地与标准LQC一致。 显示英文摘要

摘要： The relation between standard Loop Quantum Cosmology and full Loop Quantum Gravity fails already at the first nontrivial step: The configuration space of Loop Quantum Cosmology can not be embedded into the configuration space of full Loop Quantum Gravity due to a topological obstruction. We investigate this obstruction in detail, because many topological obstructions are the source of physical effects. For this we derive the topology of a large class of subspaces of the Loop Quantum Gravity configuration space. This allows us to find the extension of the standard Loop Quantum Cosmology configuration space that admits an embedding in agreement with Fleischhack:2010. We then construct the embedding for flat FRW Loop Quantum Cosmology and find that it coincides asymptotically with standard LQC.