论文标题
可压缩全息相中的零声音和更高形式的对称性
Zero sound and higher-form symmetries in compressible holographic phases
论文作者
论文摘要
具有全局u（1）对称性的物质的某些全息状态在零温度下支持声音模式，既不是由全局u（1）的自发对称性破坏，也不是由于红外中的费米表面的出现。在这项工作中，我们表明在零密度全息量子关键状态中也发现了这种模式。我们证明，在这些状态下，零温度声模式的出现是全局u（1）对称性和出现的高格式对称性之间混合hhoft异常的结果。在非零温度下，黑洞地平线的存在薄弱地打破了出现的对称性并缝制了集体模式，从而在电导率中引起了尖锐的drude峰。当状态具有出现的Lorentz对称性时，在低温下，在低温下出现了类似的间隙模式，这也源自近似异常的高色对称性。但是，在这种情况下，集体激发无法在零温度下生存，而是由于红外，临界自由度的强烈反应而溶解在分支切割中。我们评论结果与Luttinger定理在可压缩物质全息状态之间的应用之间的关系。
Certain holographic states of matter with a global U(1) symmetry support a sound mode at zero temperature, caused neither by spontaneous symmetry breaking of the global U(1) nor by the emergence of a Fermi surface in the infrared. In this work, we show that such a mode is also found in zero density holographic quantum critical states. We demonstrate that in these states, the appearance of a zero temperature sound mode is the consequence of a mixed `t Hooft anomaly between the global U(1) symmetry and an emergent higher-form symmetry. At non-zero temperatures, the presence of a black hole horizon weakly breaks the emergent symmetry and gaps the collective mode, giving rise to a sharp Drude-like peak in the electric conductivity. A similar gapped mode arises at low temperatures for non-zero densities when the state has an emergent Lorentz symmetry, also originating from an approximate anomalous higher-form symmetry. However, in this case the collective excitation does not survive at zero temperature where, instead, it dissolves into a branch cut due to strong backreaction from the infrared, critical degrees of freedom. We comment on the relation between our results and the application of the Luttinger theorem to compressible holographic states of matter.
