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Huidan Zheng

Publications and source records attributed to Huidan Zheng.

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An Entanglement-Assisted Stabilizer Framework for Distributed Sensing of Local Phases

Distributed quantum sensing requires spatially separated probes to acquire local parameters while maintaining compatibility with network-level quantum information processing. We develop an entanglement-assisted stabilizer framework based on the extended structure of entanglement-assisted quantum error-correcting (EAQEC) codes, in which the remote halves of pre-shared ebits are used directly as local phase probes while the joint state simultaneously carries an encoded logical subsystem. Each remote probe acquires a local Z-axis phase and subsequently returns through an X-type noise channel. Within the extended EAQEC stabilizer structure, the stabilizer containing $X_{B_j}$ provides phase-dependent measurement statistics, whereas its partner containing $Z_{B_j}$ records the corresponding return-error syndrome. A graph-code formulation is introduced to make this structure explicit, together with an illustrative [[5,1,3;2]] construction. We further show that, conditioned on the joint sensing-and-syndrome measurement record, the post-sensing state differs from the original encoded state only by a known Pauli transformation, so that the logical information remains available for subsequent encoded operations. For the local-phase model considered here, the stabilizer readout attains the available quantum Fisher information, while the finite-shot estimator approaches the corresponding $1/\sqrt{M}$ scaling as the number of repetitions increases. The framework therefore provides a common entanglement-assisted stabilizer structure for distributed local-phase sensing, restricted return-error identification, and post-sensing logical-state retention, without relying on an intrinsic metrological enhancement from EAQEC itself.

quant-ph

Improving Entanglement Resilience in Quantum Memories with Error-Detection-Based Distillation

The degradation of entanglement in quantum memories due to decoherence is a critical challenge for scalable quantum networks. We present an entanglement distillation protocol based on the [[4,2,2]] quantum error-detecting code, deriving analytical expressions for its output fidelity and yield, and benchmarking it against the BBPSSW protocol. In addition to single round performance, we further examine the iterative behavior of both protocols through multi-round fidelity and cumulative yield analysis. We then investigate a storage-stage recovery strategy in which the retained logical entangled state is subjected to repeated stabilizer-based syndrome checks without decoding and re-encoding, avoiding the need to regenerate and redistribute entanglement from scratch. Our analysis shows that this strategy can extend the usable storage lifetime beyond the BBPSSW baseline when the classical communication latency is sufficiently small. We derive latency thresholds and quantify the cumulative acceptance probabilities for different numbers of syndrome checks. A sensitivity analysis further shows that local gate and measurement errors reduce the fidelity advantage region and the admissible communication latency window, highlighting the importance of sufficiently accurate local operations. These results provide a quantitative framework for assessing the storage-stage benefit of logical state retention in the presence of finite communication latency and nonideal local operations.

quant-ph