Abstract:

In superconducting Quantum Measurement and Control （QMC）， the interval between consecutive measurements （referred to as the measurement gap） is a critical phase in the control sequence. It is typically configured to be several times the qubit energy relaxation time， significantly exceeding the duration of actual signal transmission and acquisition， which results in substantial idle waiting time. To address this issue， a variable trigger-based optimization method was proposed. Firstly， a temporal model of the QMC process was established， and the trigger period was identified as the key factor limiting throughput. And experimental results further verified a “non-sensitive interval” of QMC’s effectiveness to the trigger period. Based on this， a mechanism was designed to adjust the trigger period dynamically according to the actual qubit relaxation time without specialized chip design required by Reset gate or extremely low-latency control equipment needed in Restless measurement. Simulation results show that for typical system with relaxation time values between 100 μs and 500 μs， the proposed method can improve the throughput of QMC by 2-6 times， compared to the conventional method using a fixed trigger period （4 times of relaxation time）. When relaxation time is increased to 1 000 μs， the predicted throughput is improved by 10 times approximately with QMC’s effectiveness not damaged. It can be seen that the proposed method provides a software-level solution to enhance the measurement and control efficiency of large-scale superconducting quantum systems without hardware modifications and being easy to integrate and deploy， demonstrating significant practical value.

Key words: superconducting quantum computing, Quantum Measurement and Control (QMC), measurement and control throughput, variable trigger

摘要：

超导量子测控（QMC）中，2次测量之间的空隙（或称测量间隙）作为测控流程中的关键环节常被设置为量子比特能量弛豫时间的数倍，远大于实际信号发送和采集的时间，导致产生大量的空闲等待时间。针对这个问题，提出一种基于可变触发的优化方法。首先，对QMC流程进行时间建模，识别出触发周期是限制吞吐率的关键因素；其次，通过实验验证QMC有效性对触发周期变化存在一个“非敏感区间”；并在此基础上，设计一种可根据量子比特实际弛豫时间动态调整触发周期的机制，该机制无需像基于Reset门的方案那样依赖芯片特殊设计，也无需像Restless测量那样要求测控设备具备极高实时性。仿真实验结果表明：在弛豫时间为100~500 μs的典型系统上，与采用固定触发周期（4倍弛豫时间）的传统方法相比，所提方法可将QMC吞吐率提升至原来的2~6倍；当弛豫时间提升至1 000 μs时，预计吞吐率可提升至原来的近10倍，同时能保证QMC有效性不受损。所提方法为提升大规模超导量子系统的测控效率提供了一种无需硬件改动且易于集成部署的软件级解决方案，具有显著的实用价值。

关键词: 超导量子计算, 量子测控, 测控吞吐率, 可变触发