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arXiv 0903.0628hep-th
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黑D5膜中QCD的全息对偶

Holographic Dual of QCD from Black D5 Branes

Benjamin A. Burrington, Jacob Sonnenschein

摘要:

我们研究了在近极值D5膜背景下探测D 7 $\overline{\rm D7}$味探测膜的动力学性质。这个模型是一个全息对偶规范理论与自发破缺的$U(N_f)_L\times U(N_f)_R$手征对称性。两个这样的D 7 $\overline{\rm D7}$嵌入的谱,包含一个来自世界体积U(1)规范场的单个大质量四维介子,π介子,和一个来自膜嵌入涨落的单个大质量四维标量介子。此外,由于有效势在径向上的有限高度,存在连续的五维态。我们研究了这个模型中的重子,发现由于D 7世界体积作用量中的Chern-Simons项,重子的大小是稳定的。该模型允许Hagedorn温度为$\frac{1}{2πR}$,其中$R$是D5膜度规中的半径参数。我们调查的手征对称性破缺的模式在退禁闭阶段作为一个函数的膜$L$的渐近分离。我们发现,对于$\fracπ{3}R<L\lessapprox 1.068 R$,手征对称性被恢复,并且对于$L$,手征对称性在此窗口之外被破坏。我们进一步论证了具有$L<\fracπ{3}$的解仅是经典稳定的,事实上在这些边界条件下不存在D 7嵌入。

英文摘要:

We study the dynamics of probe D7 $\overline{\rm D7}$ flavor probe branes in the background of near extremal D5 branes. This model is a holographic dual to a gauge theory with spontaneous breaking of a $U(N_f)_L\times U(N_f)_R$ chiral symmetry. The spectrum of two such D7 $\overline{\rm D7}$ embeddings, contains a single massive 4D meson coming from the world volume U(1) gauge field, the pion, and a single massive 4D scalar meson coming from fluctuations of the embedding of the brane. In addition, there are continuum five dimensional states due to the finite height of the effective potential in the radial direction. We investigate baryons in this model, and find that the size is stabilized due to the Chern-Simons term in the D7 world volume action. The model admits a Hagedorn temperature of $\frac{1}{2πR}$ where $R$ is the radius parameter in the D5 branes metric. We investigate the pattern of chiral symmetry breaking in the deconfined phase as a function of the asymptotic separation of the branes $L$. We find that for $\fracπ{3}R<L\lessapprox 1.068 R$ that chiral symmetry is restored, and that chiral symmetry is broken for $L$ outside this window. We further argue that the solutions with $L<\fracπ{3}$ are only classically stable, and in fact no D7 embedding exists with these boundary conditions.

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