Stable Symmetry-Protected Topological Phases in Systems with Heralded Noise

• URL: http://arxiv.org/abs/2404.16962v3
• Date: Thu, 09 Jan 2025 19:47:13 GMT
• Title: Stable Symmetry-Protected Topological Phases in Systems with Heralded Noise
• Authors: Sanket Chirame, Fiona J. Burnell, Sarang Gopalakrishnan, Abhinav Prem,
• Abstract summary: We present a family of local quantum channels whose steady-states exhibit stable mixed-state symmetry-protected topological (SPT) order. We construct a correction protocol that confines errors into short-ranged pairs in the steady-state. As the rate of heralded noise increases, SPT order is eventually lost through a directed percolation transition.
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• Abstract: We present a family of local quantum channels whose steady-states exhibit stable mixed-state symmetry-protected topological (SPT) order. Motivated by recent experimental progress on "erasure conversion" techniques that allow one to identify ($\textit{herald}$) decoherence processes, we consider open systems with biased erasure noise, which leads to strongly symmetric heralded errors. We utilize this heralding to construct a local correction protocol that effectively confines errors into short-ranged pairs in the steady-state. Using a combination of numerical simulations and mean-field analysis, we show that our protocol stabilizes SPT order against a sufficiently low rate of decoherence. As the rate of heralded noise increases, SPT order is eventually lost through a directed percolation transition. We further find that while introducing unheralded errors destroys SPT order in the limit of long length- and time-scales, the correction protocol is sufficient for ensuring that local SPT order persists, with a correlation length that diverges as $\xi \sim (1-f_e)^{-1/2}$, where $f_e$ is the fraction of errors that are heralded.

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