论文标题
来自ADS/CFT的Weyl Semimetal带有风味
A Weyl Semimetal from AdS/CFT with Flavour
论文作者
论文摘要
我们使用$（3+1）$ - 尺寸$ \ Mathcal {n} = 4 $ supersymmetric $ su（n_c）$ yang-mills理论，以大$ n_c $和强的耦合，将$ n_f $ n_f \ ll n _c coupl构建$（3+1）$ - 尺寸$ \ Mathcal {n} = 4 $ supersymmetric $ su（n_c）$ n_c $ and n_c $ and n _f $ n_f \ ll n_c coupl， Hypermultiplets带有质量$ M $。 R-对称的A $ U（1）$亚组作用于Hypermultiplet Fermions作为轴向对称性。在存在空间方向的恒定外部轴向量规场的情况下，我们发现了Weyl半金属的定义特征：量子相变为$ m/b $，从具有非零的异常霍尔电导率到琐碎绝缘子的拓扑状态增加。过渡是一阶。值得注意的是，异常的霍尔电导率独立于超高质量，占轴向异常所决定的值。在非零温度下，过渡仍然是一阶，并且异常的霍尔电导率获得了对超人质量和温度的非平凡依赖性。
We construct a top-down holographic model of Weyl semimetal states using $(3+1)$-dimensional $\mathcal{N}=4$ supersymmetric $SU(N_c)$ Yang-Mills theory, at large $N_c$ and strong coupling, coupled to a number $N_f \ll N_c$ of $\mathcal{N}=2$ hypermultiplets with mass $m$. A $U(1)$ subgroup of the R-symmetry acts on the hypermultiplet fermions as an axial symmetry. In the presence of a constant external axial gauge field in a spatial direction, $b$, we find the defining characteristic of a Weyl semi-metal: a quantum phase transition as $m/b$ increases, from a topological state with non-zero anomalous Hall conductivity to a trivial insulator. The transition is first order. Remarkably, the anomalous Hall conductivity is independent of the hypermultiplet mass, taking the value dictated by the axial anomaly. At non-zero temperature the transition remains first order, and the anomalous Hall conductivity acquires non-trivial dependence on the hypermultiplet mass and temperature.
