论文标题
平衡的翻译不变系统的阶段：迭代绿色的功能技术和重新归一化组方法
Phases of translation-invariant systems out of equilibrium: Iterative Green's function techniques and renormalization group approaches
论文作者
论文摘要
我们介绍了一种评估稳态的非平衡Keldysh-Schwinger Green功能的无限系统功能，并遵循储层的耦合。我们提出的方法利用了物理准翻译不变性，如果所有电子能量都通过电场的大小同时移动，那么一个单位细胞的转移会使物理不变。我们的框架是直接适用于示意性多体方法的。我们讨论两个旗舰应用，平均场理论以及复杂的二阶功能重新归一化组方法。后者使我们能够将晶格费米子的相变的重新归一化组表征推向非平衡领域。我们通过研究一个无旋转费米的模型来体现这一点，该模型在平衡中表现出Berezinskii-Kosterlitz-无尽的相变。
We introduce a method to evaluate the steady-state non-equilibrium Keldysh-Schwinger Green's functions for infinite systems subject to both an electric field and a coupling to reservoirs. The method we present exploits a physical quasi-translation invariance, where a shift by one unit cell leaves the physics invariant if all electronic energies are simultaneously shifted by the magnitude of the electric field. Our framework is straightaway applicable to diagrammatic many-body methods. We discuss two flagship applications, mean-field theories as well as a sophisticated second-order functional renormalization group approach. The latter allows us to push the renormalization-group characterization of phase transitions for lattice fermions into the out-of-equilibrium realm. We exemplify this by studying a model of spinless fermions, which in equilibrium exhibits a Berezinskii-Kosterlitz-Thouless phase transition.
