标题： N=4 拓扑弦 显示英文标题

标题： N=4 Topological Strings

摘要： 我们展示如何从$N=4$超共形理论出发构建一种拓扑弦论。 该理论的临界维数为$\hat c= 2$($c=6$)。 已证明超弦（在RNS和GS形式下）和临界$N=2$弦是这种拓扑理论的特例。 这种新的拓扑理论的应用包括：1）证明自对偶$N=2$弦在平坦背景下的所有散射振幅在所有阶次下都为零，除了三点函数和闭弦划分函数；2）表明在$K3$背景下$N=2$弦的拓扑划分函数可以解释为计算将II型超弦从10维紧致化到6维时在调和超空间中生成的超势；以及3）提供一种计算超弦振幅的新方法，该方法似乎不受全导数歧义的影响。 显示英文摘要

摘要： We show how to make a topological string theory starting from an $N=4$ superconformal theory. The critical dimension for this theory is $\hat c= 2$ ($c=6$). It is shown that superstrings (in both the RNS and GS formulations) and critical $N=2$ strings are special cases of this topological theory. Applications for this new topological theory include: 1) Proving the vanishing to all orders of all scattering amplitudes for the self-dual $N=2$ string with flat background, with the exception of the three-point function and the closed-string partition function; 2) Showing that the topological partition function of the $N=2$ string on the $K3$ background may be interpreted as computing the superpotential in harmonic superspace generated upon compactification of type II superstrings from 10 to 6 dimensions; and 3) Providing a new prescription for calculating superstring amplitudes which appears to be free of total-derivative ambiguities.