量子处理器上退相干诱导的平均对称保护拓扑相的实现
Realization of decoherence-induced averaged symmetry-protected topological phases on quantum processors
- National University of Singapore（新加坡国立大学）
- Eastern Institute of Technology, Ningbo（宁波东方理工大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本工作在可编程量子处理器上实现了退相干诱导的平均对称保护拓扑序，通过辅助量子比特设计子晶格选择性退相干，观测到对称荷衰减和Renyi-2弦关联函数非平凡，确立了结构化退相干作为工程混合态拓扑物质的资源。
AI中文摘要：
对称保护拓扑（SPT）相通常被表述为受精确对称性保护的纯态。然而，在开放量子系统中，退相干会产生混合态系综，其中平均对称性只能在对微观轨迹进行平均后才出现。在本工作中，我们在可编程量子处理器上实现了退相干诱导的平均SPT（ASPT）序。从一维团簇SPT态出发，我们通过辅助量子比特辅助的量子电路设计了子晶格选择性泡利-Z退相干。我们通过对称荷的衰减观察到了由此产生的对称性转换。此外，通过破坏性SWAP读出测量的双副本Renyi-2弦关联函数保持非平凡，揭示了编码在密度矩阵层面的ASPT结构。我们进一步表明，所设计的退相干在约化稳定子扇区之间重新分配了谱权重，同时保持了半链纠缠谱的特征性二重配对。这些结果建立了一条基于门电路的工程和探测ASPT序的途径，并证明了结构化退相干作为实现混合态拓扑量子物质的可编程资源。
英文摘要：
Symmetry-protected topological (SPT) phases are conventionally formulated for pure states protected by exact symmetries. In open quantum systems, however, decoherence generates mixed-state ensembles in which average symmetry can instead emerge only after averaging over microscopic trajectories. In this work, we realize decoherence-induced averaged SPT (ASPT) order on programmable quantum processors. Starting from a one-dimensional cluster SPT, we engineer sublattice-selective Pauli-$Z$ dephasing through ancilla-assisted quantum circuits. We observe the resulting symmetry conversion through the decay of the symmetry charge. Moreover, a two-replica Renyi-2 string correlator measured through destructive SWAP readout remains nontrivial, revealing the ASPT structure encoded at the density-matrix level. We further show that the engineered dephasing redistributes spectral weight among reduced-stabilizer sectors while preserving the characteristic twofold pairing of the half-chain entanglement spectrum. These results establish a gate-based route to engineering and probing ASPT order and demonstrate structured decoherence as a programmable resource for realizing mixed-state topological quantum matter.
