论文标题
从量子蒙特卡洛数据中鉴定非弗米液体效率自我能源
Identification of non-Fermi liquid fermionic self-energy from quantum Monte Carlo data
论文作者
论文摘要
相关电子系统的量子蒙特卡洛（QMC）模拟提供了有关量子临界点（QCP）系统行为的无偏信息，并可以验证或反驳QCP上非Fermi液体（NFL）行为的现有理论。但是，在有限的量子特征被有限的温度效果掩盖的有限温度下进行模拟。在这里，我们提出了一个理论框架，可以在其中分离热和量子效应，并在$ t = 0 $时提取有关NFL物理的信息。我们证明了我们的方法，用于在Ising-Ferromagnetic QCP附近的2D费米子的特定示例。我们显示，即使对自我能源的主要贡献来自热效应，也可以从QMC数据中提取零温度形式的零温度形式。我们发现，$σ（ω）$的频率依赖性与在Eliashberg的动态量子关键性理论中获得的分析形式非常吻合，并且在低频下遵守$ω^{2/3} $。我们的结果为QMC关键金属研究开辟了一条途径。
Quantum Monte Carlo (QMC) simulations of correlated electron systems provide unbiased information about system behavior at a quantum critical point (QCP) and can verify or disprove the existing theories of non-Fermi liquid (NFL) behavior at a QCP. However, simulations are carried out at a finite temperature, where quantum-critical features are masked by finite temperature effects. Here we present a theoretical framework within which it is possible to separate thermal and quantum effects and extract the information about NFL physics at $T=0$. We demonstrate our method for a specific example of 2D fermions near a Ising-ferromagnetic QCP. We show that one can extract from QMC data the zero-temperature form of fermionic self-energy $Σ(ω)$ even though the leading contribution to the self-energy comes from thermal effects. We find that the frequency dependence of $Σ(ω)$ agrees well with the analytic form obtained within the Eliashberg theory of dynamical quantum criticality, and obeys $ω^{2/3}$ scaling at low frequencies. Our results open up an avenue for QMC studies of quantum-critical metals.
