论文标题
Ising链具有耗散诱导的拓扑变性
Ising chain with topological degeneracy induced by dissipation
论文作者
论文摘要
当量子自旋系统的基础变性是非平凡拓扑的一个特征，当它与无序的扰动中相处和稳健性时。相应的量子相变（QPT）通常由真实参数驱动。我们基于精确的解决方案和数值模拟研究了一个具有两个横向场的非热伊斯林链，一个是真实的和另一个假想的。我们表明，拓扑变性仍然存在，可以通过从遗传学系统的拓扑阶段进行虚构的横向场获得。拓扑变性对随机假想场是可靠的，因此预计在实验中自发性衰变会免疫无序的耗散。潜在的机制是非局部对称性，它仅以热力学极限出现，并分别与量子自旋系统中的两类QPT相关联，分别源于拓扑顺序和对称性断裂。
The ground-state degeneracy of the quantum spin system is a characteristic of nontrivial topology, when it is gapped and robust against disordered perturbation. The corresponding quantum phase transition (QPT) is usually driven by a real parameter. We study a non-Hermitian Ising chain with two transverse fields, one real and another imaginary, based on the exact solution and numerical simulation. We show that topological degeneracy still exists and can be obtained by an imaginary transverse field from a topologically trivial phase of a Hermitian system. The topological degeneracy is robust against the random imaginary field and therefore expected to be immune to disordered dissipation from the spontaneous decay in experiment. The underlying mechanism is the nonlocal symmetry, which emerges only in thermodynamic limit and relates two categories of QPTs in the quantum spin system, rooted from topological order and symmetry breaking, respectively.
