论文标题
SYK模型的量子不连续点固定点和重新归一化组流动
Quantum discontinuity fixed point and renormalization group flow of the SYK model
论文作者
论文摘要
我们确定了Sachdev-Ye-Kitaev（SYK）模型的全局重归其化组（RG）流。这种流程可以理解在强相关的电子系统中，在量子一阶转变处临界减速的令人惊讶的作用。从确切功能性RG流程方程的无限层次结构的简单截断，我们确定了几个固定点：除了稳定的固定点外，与著名的非Fermi液体状态相关的稳定固定点，我们发现了另一个与整数价值状态相关的稳定固定点。这些稳定的固定点由一个相关方向的不连续性固定点隔开，描述了量子一阶跃迁。最值得注意的是，即使在不连续点的固定点，费米子频谱也仍然是量子关键的。这排除了该量子一阶过渡的描述，该量子过渡是为经典过渡而建立的局部有效ISING变量的描述。它表明，量子相共存可能是物质的真正临界状态。
We determine the global renormalization group (RG) flow of the Sachdev-Ye-Kitaev (SYK) model. This flow allows for an understanding of the surprising role of critical slowing down at a quantum first-order transition in strongly-correlated electronic systems. From a simple truncation of the infinite hierarchy of the exact functional RG flow equations we identify several fixed points: Apart from a stable fixed point, associated with the celebrated non-Fermi liquid state of the model, we find another stable fixed point related to an integer-valence state. These stable fixed points are separated by a discontinuity fixed point with one relevant direction, describing a quantum first-order transition. Most notably, the fermionic spectrum continues to be quantum critical even at the discontinuity fixed point. This rules out a description of this quantum first-order transition in terms of a local effective Ising variable that is established for classical transitions. It reveals that quantum phase coexistence can be a genuine critical state of matter.
