标题： 量子引力作为变形的拓扑量子场论 显示英文标题

标题： Quantum Gravity as a Deformed Topological Quantum Field Theory

摘要： 已知带有正宇宙常数的爱因斯坦-希尔伯特作用量可以表示为SO(4,1) BF理论的微扰，该微扰由一个关于B场二次的对称性破缺项构成。引入费米物质会在作用量中产生额外的项，这些项是四维标架和自旋连接的多项式。我们描述了如何在存在B场和规范场源的情况下，针对一般的BF理论在自旋泡沫形式主义中构造生成泛函。该泛函可用于获得包含物质的广义相对论的路径积分，作为一个微扰级数，其最低阶项是一个与物质耦合的拓扑引力的路径积分。 显示英文摘要

摘要： It is known that the Einstein-Hilbert action with a positive cosmological constant can be represented as a perturbation of the SO(4,1) BF theory by a symmetry-breaking term quadratic in the B field. Introducing fermionic matter generates additional terms in the action which are polynomial in the tetrads and the spin connection. We describe how to construct the generating functional in the spin foam formalism for a generic BF theory when the sources for the B and the gauge field are present. This functional can be used to obtain a path integral for General Relativity with matter as a perturbative series whose the lowest order term is a path integral for a topological gravity coupled to matter.