发表机构
Universidad Autónoma de Madrid; Instituto Superior Técnico, Universidade de Lisboa; University of Stuttgart; Jagiellonian University; Polish Academy of Sciences; OsloMet – Oslo Metropolitan University（马德里自治大学; 里斯本大学高级理工学院; 斯图加特大学; 雅盖隆大学; 波兰科学院; 奥斯陆都会大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究针对耗散随机量子电路，推导了平均保真度的闭式表达式，明确了耗散等参数对保真度衰减的影响，区分了耗散效应与相干噪声的可识别场景。
AI 中文摘要
当前的量子处理器是开放系统，在量子态沿电路传播时，耗散与退相干会降低其携带的信息。我们研究耗散随机量子电路中的这种退化，将每个两量子比特门建模为稀释幺正操作，它在目标幺正操作与随机耗散量子通道之间插值。以理想输出态与噪声输出态之间的保真度作为诊断量，我们证明足够随机的幺正门或耗散 Kraus 算子会导致平均保真度的普适衰减。该衰减仅由耗散强度、系统规模和电路深度决定，而门与噪声的微观细节（包括 Kraus 秩）仅出现在更高阶矩的次主导修正项中。我们基于三个具有物理意义的误差参数（耗散强度、相干两量子比特门误差强度、连通性误差概率）推导了平均保真度的闭式表达式。最后，我们确定了两种情况：一是耗散效应可由幺正噪声模型重现，二是在平均保真度层面，耗散诱导的退相干仍可与相干噪声区分开。
英文摘要
Present-day quantum processors are open systems in which dissipation and decoherence degrade the information carried by a quantum state as it propagates through a circuit. We study this degradation in dissipative random quantum circuits, modeling each two-qubit gate as a diluted unitary that interpolates between the intended unitary operation and a random dissipative quantum channel. Using the fidelity between the ideal and noisy output states as a diagnostic, we show that sufficiently random unitary gates or dissipative Kraus operators lead to a universal decay of the average fidelity. This decay is determined only by the dissipation strength, system size, and circuit depth, while microscopic details of the gates and noise, including the Kraus rank, appear only in subleading corrections to higher moments. We derive a closed-form expression for the average fidelity in terms of three physically meaningful error parameters, dissipation strength, coherent two-qubit gate-error strength, and connectivity-error probability. Finally, we identify the cases when dissipative effects can be reproduced by an unitary-noise model and when dissipation-induced decoherence remains distinguishable from coherent noise at the level of the average fidelity.
Comments10 pages main text, 12 pages supplemental material and 6 figures
