论文标题
3D Hofstadter模型中强大的非平衡表面电流
Robust nonequilibrium surface currents in the 3D Hofstadter model
论文作者
论文摘要
自从发现其一维对应物以来，真正缺少朝着热通量的自然方向流动的二维强大杂交 - 朝着自然的方向流动。我们提供了一个设置，以在一个三维（3D）晶格上实现它们，该晶格托有一个霍夫史塔特模型，并与两个温度不同的热浴耦合。我们表明这些电流表现出耗散性的鲁棒性：它们在某些非平衡构型中具有杂质和量规场的倾斜性而稳定。此外，我们发现具有真正3D鲁棒性的受保护边界电流，即只有在所有三个空间方向都会发生隧道时才稳定。该模型还呈现通用表面电流，对玻感和费米子系统都具有鲁棒性。我们确定了负责表面电流鲁棒性的潜在定性机制以及某些离散对称性的关键作用。
Genuinely two-dimensional robust crosscurrents -- which flow against the natural direction of heat flux -- have been missing since the discovery of their one-dimensional counterpart. We provide a setup to realize them on a cubic three-dimensional (3D) lattice hosting a Hofstadter model coupled to two heat baths with different temperatures. We show that these currents exhibit dissipative robustness: they are stable against the presence of impurities and tilting of the gauge field in certain nonequilibrium configurations. Moreover, we find protected boundary currents with genuinely 3D robustness, i.e. they are only stable if tunnelling can occur in all three spatial directions. The model also presents generic surface currents, which are robust for both bosonic and fermionic systems. We identify the underlying qualitative mechanism responsible for the robustness of the surface currents and the crucial role played by certain discrete symmetries.
