论文标题
弦理论雪茄的半古典分析
Semi-Classical Analysis of the String Theory Cigar
论文作者
论文摘要
我们研究了SL（2，r）_K/U（1）CFT的反射系数的半古典限制。对于大K，CFT描述了二维Dilaton-Gravity的欧几里得黑洞中的一根弦，其目标空间是具有渐近线性dilaton的雪茄。这种Sigma模型描述在较大的K限制中弱耦合，我们研究了计算反射系数的功能积分的鞍点扩展。就像在liouville CFT的半古典限制中一样，我们发现必须将功能积分和总和复杂化，并在复杂的马鞍上复杂以重现精确反射系数的极限。与liouville不同，SL（2，R）_K/U（1）CFT接纳表现为反射系数的极线的界面。为了在半古典限制中重现它们，我们发现必须对击中黑洞奇异性的配置进行概括，但仍会通过有限的动作有助于鞍点的扩展。
We study the semi-classical limit of the reflection coefficient for the SL(2,R)_k/U(1) CFT. For large k, the CFT describes a string in a Euclidean black hole of 2-dimensional dilaton-gravity, whose target space is a cigar with an asymptotically linear dilaton. This sigma-model description is weakly coupled in the large k limit, and we investigate the saddle-point expansion of the functional integral that computes the reflection coefficient. As in the semi-classical limit of Liouville CFT, we find that one must complexify the functional integral and sum over complex saddles to reproduce the limit of the exact reflection coefficient. Unlike Liouville, the SL(2,R)_k/U(1) CFT admits bound states that manifest as poles of the reflection coefficient. To reproduce them in the semi-classical limit, we find that one must sum over configurations that hit the black hole singularity, but nevertheless contribute to the saddle-point expansion with finite action.
