论文标题
在非铁量量子步行中的拓扑阶段的持久性
Persistence of Topological Phases in Non-Hermitian Quantum Walks
论文作者
论文摘要
已知离散时间量子步行会表现出外来拓扑状态和相。在嘈杂的环境中进行量子行走的物理实现可能会破坏这些阶段。我们在存在有损环境的情况下研究了拓扑状态在量子步行中的行为。量子步行动力学中的环境效应是使用非热汉尔顿的方法来解决的。我们表明，量子步行的拓扑阶段对于中等损失是可靠的。只要哈密顿量为$ \ MATHCAL {pt} $ - 对称性，一维拆分量子步行中的拓扑顺序就可以持续存在。尽管拓扑性质在二维量子步行中也持续存在，但$ \ Mathcal {pt} $ - 对称性没有作用。此外，我们观察到二维量子步行中噪声诱导的拓扑相变。
Discrete-time quantum walks are known to exhibit exotic topological states and phases. Physical realization of quantum walks in a noisy environment may destroy these phases. We investigate the behavior of topological states in quantum walks in the presence of a lossy environment. The environmental effects in the quantum walk dynamics are addressed using the non-Hermitian Hamiltonian approach. We show that the topological phases of the quantum walks are robust against moderate losses. The topological order in one-dimensional split-step quantum walk persists as long as the Hamiltonian is $\mathcal{PT}$-symmetric. Although the topological nature persists in two-dimensional quantum walks as well, the $\mathcal{PT}$-symmetry has no role to play there. Furthermore, we observe the noise-induced topological phase transition in two-dimensional quantum walks.
