Realization of decoherence-induced averaged symmetry-protected topological phases on quantum processors
Abstract
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.
Related
- Barycentric programming: Classical realization of programs for universal quantum processors
- Predicting Entanglement Spectra of Gapless Symmetry-Protected Topological States in One Dimension
- Symmetry-permuting entanglers for non-invertible symmetry-protected topological phases
- Topological Phenomena Protected by Diabolical Textures
- Experimental Realization of Higher-order Topological Water Wave Crystal
BibTeX
@misc{shen2026realization,
title = {{Realization of decoherence-induced averaged symmetry-protected topological phases on quantum processors}},
author = {Ruizhe Shen and Xue-Jia Yu and Ching Hua Lee},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.07831},
eprint = {2609.07831},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.07831},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Realization of decoherence-induced averaged symmetry-protected topological phases on quantum processors
AU - Ruizhe Shen
AU - Xue-Jia Yu
AU - Ching Hua Lee
PY - 2026
DA - 2026/09/07
PB - arXiv
DO - 10.48550/arxiv.2609.07831
UR - https://arxiv.org/abs/2609.07831
AB - 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.
ER -