近日，山东大学赵培茈团队研究了几何量子计算的消相干缓解。2025年9月2日，《物理评论A》杂志发表了这一成果。

几何相位只依赖于由投影Hilbert空间中的闭环所决定的演化路径，而不依赖于量子系统的演化细节，这使得几何量子计算对控制误差具有一定的内在稳定性。与动态解耦相协调，几何量子计算对环境诱导的退相干具有额外的弹性。然而，以往采用动态解耦保护的几何量子计算方案需要多个物理量子位来编码一个逻辑量子位，这无疑增加了物理量子位资源的消耗和基于物理量子位驱动的逻辑量子位操作的实现难度。

在这项工作中，研究组提出了一种仅基于物理量子位而不是逻辑量子位的消相干几何量子计算方案，从而避免了逻辑量子位编码的物理量子位资源的额外开销以及逻辑量子位的操作困难。此外，该方案侧重于单个量子比特与其环境之间最普遍的相互作用，因此它不仅减轻了它们的减相噪声，还减轻了规则的退相干。该建议代表了一个更现实和有效的方法来实现几何控制与消相干缓解。

附：英文原文

Title: Decoherence mitigation for geometric quantum computation

Author: X. Y. Sun, P. Z. Zhao

Issue&Volume: 2025/09/02

Abstract: Geometric phases depend only on the evolution path determined by the closed circuit in the projective Hilbert space but not on evolution details of the quantum system, leading to geometric quantum computation possessing some intrinsic robustness against control errors. Coordinated with dynamical decoupling, geometric quantum computation admits additional resilience to the environment-induced decoherence. However, the previous schemes of geometric quantum computation protected by dynamical decoupling require multiple physical qubits to encode a logical qubit, which undoubtedly increases the consumption of physical-qubit resources and the difficulty in the implementation of the logical-qubit manipulation based on physical-qubit driving. In this work, we put forward a scheme of decoherence-mitigated geometric quantum computation based only on physical qubits rather than logical qubits, hence avoiding the additional overhead of physical-qubit resources for logical-qubit encoding as well as the difficulty in the manipulation of logical qubits. Moreover, our scheme focuses on the most general interaction between an individual qubit and its environment so that it mitigates not just dephasing noise but rather regular decoherence. Our proposal thus represents a more realistic and effective approach towards the realization of geometric control with decoherence mitigation.

DOI: 10.1103/7y8p-85k3

Source: https://journals.aps.org/pra/abstract/10.1103/7y8p-85k3