PT-symmetry berry phases, topology and PT-symmetry breaking
PT-symmetry berry phases, topology and PT-symmetry breaking
复制标题
PT 对称浆果相、拓扑和 PT 对称性破缺
DOI：
10.1088/1572-9494/ab5fb5
复制
发表时间：
2020
影响因子：
3.1
通讯作者：
Lu Rong
中科院分区：
文献类型：
--
作者：
Pi Jinghui;Sun Ningning;Lu Rong
研究了具有宇称和时间反演对称性的非厄米系统中的复Berry相位。研究了一类具有PT对称性的二能级系统。我们发现复Berry相位的真实的部分有两个量子化值，它们分别等于0或π，这源于厄米特本征态的拓扑结构。我们还发现，如果我们改变哈密顿量的相对参数，从未破缺的PT对称相到破缺的PT对称相，复Berry相的虚部在例外点是发散的。在这项工作中，我们展示了两个具体的例子，一个是两个层次的玩具模型，其中有非平凡的Berry相位;另一个是广义的Su-Schrieffer-Heeger（SSH）模型，在每个子晶格的物理损失和增益。我们的结果明确地揭示了复Berry相、拓扑和PT对称性破缺之间的关系，丰富了非厄米物理的研究领域。
We study the complex Berry phases in non-Hermitian systems with parity-and time-reversal (PT ) symmetry. We investigate a kind of two-level system with PT symmetry. We find that the real part of the the complex Berry phases have two quantized values and they are equal to either 0 or π, which originates from the topology of the Hermitian eigenstates. We also find that if we change the relative parameters of the Hamiltonian from the unbroken-PT-symmetry phase to the broken-PT-symmetry phase, the imaginary part of the complex Berry phases are divergent at the exceptional points. We exhibit two concrete examples in this work, one is a two-level toys model, which has nontrivial Berry phases; the other is the generalized Su–Schrieffer–Heeger (SSH) model that has physical loss and gain in every sublattice. Our results explicitly demonstrate the relation between complex Berry phases, topology and PT-symmetry breaking and enrich the field of the non-Hermitian physics.