The ability for users to access quantum computers through the cloud has increased rapidly in recent years. Despite still being Noisy Intermediate-Scale Quantum (NISQ) machines, modern quantum computers are now being actively employed for research and by numerous startups. Quantum algorithms typically produce probabilistic results, necessitating repeated execution to produce the desired outcomes. In order for the execution to begin from the specified ground state each time and for the results of the prior execution not to interfere with the results of the subsequent execution, the reset mechanism must be performed between each iteration to effectively reset the qubits. However, due to noise and errors in quantum computers and specifically these reset mechanisms, a noisy reset operation may lead to systematic errors in the overall computation, as well as potential security and privacy vulnerabilities of information leakage. To counter this issue, we thoroughly examine the state leakage problem in quantum computing, and then propose a solution by employing the classical and quantum one-time pads before the reset mechanism to prevent the state leakage, which works by randomly applying simple gates for each execution of the circuit. In addition, this work explores conditions under which the classical one-time pad, which uses fewer resources, is sufficient to protect state leakage. Finally, we study the role of various errors in state leakage, by evaluating the degrees of leakage under different error levels of gate, measurement, and sampling errors. Our findings offer new perspectives on the design of reset mechanisms and secure quantum computing systems.

翻译：近年来，用户通过云端访问量子计算机的能力迅速提升。尽管当前量子计算机仍属含噪声中等规模量子（NISQ）设备，但已被积极用于研究领域及众多初创企业。量子算法通常产生概率性结果，需重复执行以获得预期输出。为确保每次执行从指定基态开始，且前次执行结果不干扰后续执行结果，必须在每次迭代间执行重置机制以有效重置量子比特。然而，受量子计算机及其重置机制中的噪声与误差影响，含噪重置操作可能导致整体计算产生系统性误差，并引发信息泄露的安全与隐私漏洞。针对此问题，本文深入研究了量子计算中的状态泄露问题，提出在重置机制前采用经典与量子一次一密（One-Time Pad）防止状态泄露的解决方案——该方法通过为电路每次执行随机施加简单门操作实现。此外，本研究探讨了资源消耗更少的经典一次一密足以防护状态泄露的条件。最后，通过评估不同门误差、测量误差和采样误差水平下的泄露程度，系统分析了各类误差在状态泄露中的作用。研究结论为重置机制设计与安全量子计算系统构建提供了新视角。