On the stability of multiscale models of dynamical symmetry breaking from holography
On the stability of multiscale models of dynamical symmetry breaking from holography
复制标题
全息动力学对称性破缺多尺度模型的稳定性
DOI：
10.1016/j.nuclphysb.2014.01.016
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Daniel Schofield
中科院分区：
文献类型：
--
作者：
A. F. Faedo;M. Piai;Daniel Schofield
我们考虑了两类IIB型超重力背景，这两类背景是通过将d5膜包裹在con褶内的两个旋回上获得的。场论对偶表现出约束，此外，动力学在其中行走的区域，至少在弱意义上，耦合的运行异常缓慢。我们在基本理论中引入了淬灭物质，用探针d7膜来模拟，d7膜包裹着一个内部三维流形，位于横向双球的赤道。在剩余的内角和径向坐标所跨越的空间中，膜允许两个嵌入。第一个是u形的：膜在半径的某个有限值处合并。第二个是断开的，沿着整个径向以固定的角间距延伸。我们将这两种构型分别解释为手性对称破缺相和保持相。我们提出了一个简单的诊断工具来检查嵌入的经典稳定性，基于相关热力学势的凹凸条件。我们使用这一标准来证明探索行走区域的u形探针是不稳定的，从而为文献中发现的速子模式提供了一个动力学起源。每当这种情况发生时，分离的溶液就会在能量上得到青睐。我们发现，在任意一类背景下，u形嵌入总是不稳定的，因此无法实现动态嵌入。因此，这些模型不能用于描述手性对称性破缺。在第二类解中，我们的分析揭示了手性对称性破缺相和恢复相之间存在一阶相变。有趣的是，这和对偶场论中胶球光谱中包含的参数光标量是同一类的。
We consider two classes of backgrounds of Type IIB supergravity obtained by wrapping D5-branes on a two-cycle inside the conifold. The field theory dual exhibits confinement and, in addition, a region in which the dynamics is walking, at least in the weak sense that the running of the coupling is anomalously slow. We introduce quenched matter in the fundamental, modeled by probe D7-branes which wrap an internal three-dimensional manifold and lie at the equator of the transverse two-sphere. In the space spanned by the remaining internal angle and the radial coordinate, the branes admit two embeddings. The first one is U-shaped: the branes merge at some finite value of the radius. The second one is disconnected and extends along the entire radial direction at fixed angular separation. We interpret these two configurations as corresponding to chiral-symmetry breaking and preserving phases, respectively.We present a simple diagnostic tool to examine the classical stability of the embedding, based on the concavity/convexity conditions for the relevant thermodynamic potentials. We use this criterion to show that U-shaped probes that explore the walking region are unstable, hence providing a dynamical origin for the tachyonic mode found in the literature. Whenever this occurs, the disconnected solution becomes favored energetically. We find that in one of the two classes of backgrounds the U-shaped embedding is always unstable, and thus never realized dynamically. Consequently, these models cannot be used to describe chiral-symmetry breaking. In the second category of solutions, our analysis reveals the presence of a first-order phase transition between chiral-symmetry broken and restored phases. Interestingly, this is in the same class that contains a parametrically light scalar in the spectrum of glueballs of the dual field theory.
扭曲的、解析的、变形的锥体变得有味道
影响因子：
2.8
作者：
Gaillard J
通讯作者：
Gaillard J
影响因子：
5.4
作者：
Daniel Elander;J. Gaillard;C. Nunez;M. Piai
通讯作者：
Daniel Elander;J. Gaillard;C. Nunez;M. Piai
影响因子：
4.4
作者：
Elander D
通讯作者：
Elander D