Quantum phase transition in the Yukawa-SYK model
Quantum phase transition in the Yukawa-SYK model
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DOI：
10.1103/physrevresearch.2.033084
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发表时间：
2020-05
期刊：
影响因子：
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通讯作者：
Yuxuan Wang;A. Chubukov
中科院分区：
文献类型：
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作者：
Yuxuan Wang;A. Chubukov
在一个具有随机Yukawa相互作用的模型中，我们研究了费米子密度变化时的量子相变，称为Yukawa-SYK模型。我们发现模型中有两个不同的阶段：一个是有间隙激发的不可压缩态，另一个是指数随u变化的奇异量子临界非费米液态态。我们从解析和数值上证明了这两个态之间的量子相变是一级的，因为在一定范围内，NFL态具有负的可压缩性。在极限为$N/M\to\inty$时，一阶跃迁变弱，渐近变为二阶，具有奇异的量子临界行为。我们发现费米子和玻色子在过渡区表现出非常非常规的光谱行为。
We study the quantum phase transition upon variation of the fermionic density $\nu$ in a solvable model with random Yukawa interactions between $N$ bosons and $M$ fermions, dubbed the Yukawa-SYK model. We show that there are two distinct phases in the model: an incompressible state with gapped excitations and an exotic quantum-critical, non-Fermi liquid state with exponents varying with $\nu$. We show analytically and numerically that the quantum phase transition between these two states is first-order, as for some range of $\nu$ the NFL state has a negative compressibility. In the limit $N/M\to \infty$ the first-order transition gets weaker and asymptotically becomes second-order, with an exotic quantum-critical behavior. We show that fermions and bosons display highly unconventional spectral behavior in the transition region.