The Veneziano Limit of N = 2 Superconformal QCD: Towards the String Dual of N = 2 SU(N(c)) SYM with N(f) = 2 N(c)
The Veneziano Limit of N = 2 Superconformal QCD: Towards the String Dual of N = 2 SU(N(c)) SYM with N(f) = 2 N(c)
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N = 2 超共形 QCD 的 Veneziano 极限：朝向 N = 2 SU(N(c)) SYM 的弦对偶，其中 N(f) = 2 N(c)
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发表时间：
2009
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通讯作者：
L. Rastelli
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作者：
Abhijit Gadde;E. Pomoni;L. Rastelli
我们解决了寻找N=2个超共形QCD的ADS对偶，N=2个规范群为SU(N_C)和N_f=2个N_c基本超多重的N=2个超杨Mills理论的长期存在的问题。该理论允许大N_c和大N_f的Venziano展开式，且N_f/N_c和lambda=g^2 N_c保持不变。大N图的拓扑结构引发了一个普遍的猜想：Venziano极限中规范理论的味-单重态部分对偶于闭弦理论；单闭弦状态对应于“广义单迹”算符，其中伴随字母和味收缩的基本/反基本对串在一个闭链中。我们从两个方面寻找N=2超共形QCD的弦对偶。自下而上，我们使用超共形表示理论对受保护的谱进行了系统的分析。我们还评估了标量扇区的单圈膨胀算符，发现了一个新的自旋链。
从自上而下，我们考虑了已知膜结构的解耦极限。在这两种方法中，当两个规范耦合中的一个被调谐到零时，通过将理论视为N=4SYM的N=2 Z_2的简并极限，可以获得更多的见解。一幅始终如一的图景出现了。我们的结论是弦对偶是一个次临界背景，有七个“几何”维度，包含一个ADS_5和一个S^1因子。超引力近似从来都不是完全有效的，即使是对于大的波长，事实上，场论有一个指数简并的精确保护态具有更高的自旋，这必须是一个光弦态的扇区的对偶。
We attack the long-standing problem of finding the AdS dual of N = 2 superconformal QCD, the N=2 super Yang Mills theory with gauge group SU(N_c) and N_f = 2 N_c fundamental hyper multiplets. The theory admits a Veneziano expansion of large N_c and large N_f, with N_f/N_c and lambda = g^2 N_c kept fixed. The topological structure of large N diagrams motivates a general conjecture: the flavor-singlet sector of a gauge theory in the Veneziano limit is dual to a closed string theory; single closed string states correspond to "generalized single-trace" operators, where adjoint letters and flavor-contracted fundamental/antifundamental pairs are stringed together in a closed chain. We look for the string dual of N = 2 superconformal QCD from two fronts. From the bottom-up, we perform a systematic analysis of the protected spectrum using superconformal representation theory. We also evaluate the one-loop dilation operator in the scalar sector, finding a novel spin chain.
From the top-down, we consider the decoupling limit of known brane constructions. In both approaches, more insight is gained by viewing the theory as the degenerate limit of the N = 2 Z_2 orbifold of N = 4 SYM, as one of the two gauge couplings is tuned to zero. A consistent picture emerges. We conclude that the string dual is a sub-critical background with seven "geometric" dimensions, containing both an AdS_5 and an S^1 factor. The supergravity approximation is never entirely valid, even for large lambda, indeed the field theory has an exponential degeneracy of exactly protected states with higher spin, which must be dual to a sector of light string states.