Real-time adaptive estimation of decoherence timescales for a single qubit
Real-time adaptive estimation of decoherence timescales for a single qubit
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DOI：
10.1103/physrevapplied.21.024026
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发表时间：
2022-10
影响因子：
4.6
通讯作者：
M. Arshad;Christiaan J. Bekker;B. Haylock;K. Skrzypczak;Daniel White;Benjamin Griffiths;Joseph P P Gore-Joseph-P-P-Gore-2090530166;Gavin W. Morley;P. Salter;Jason Smith;Inbar Zohar;A. Finkler;Y. Altmann;E. Gauger;C. Bonato
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作者：
M. Arshad;Christiaan J. Bekker;B. Haylock;K. Skrzypczak;Daniel White;Benjamin Griffiths;Joseph P P Gore-Joseph-P-P-Gore-2090530166;Gavin W. Morley;P. Salter;Jason Smith;Inbar Zohar;A. Finkler;Y. Altmann;E. Gauger;C. Bonato
表征量子相干存在的时间对于任何量子比特、存储器和传感器的实现都是至关重要的。确定量子系统消相干速率的通常方法包括一系列实验，探测该参数的整个预期范围，并在后处理中提取结果估计。在这里，我们提出了一种基于简单的解析更新规则的自适应多参数贝叶斯方法，利用先前实验中获得的信息，实时估计量子系统的关键退相干时间尺度($T_1$，$T_2^*$和$T_2$)和相应的衰变指数。与标准曲线拟合方案相比，这种方法减少了达到给定不确定度所需的时间，最高可达一个数量级，具体取决于具体的实验。通过对灵敏度而不是方差进行优化，可以实现系数$\sim 2$的进一步加速。
Characterising the time over which quantum coherence survives is critical for any implementation of quantum bits, memories and sensors. The usual method for determining a quantum system's decoherence rate involves a suite of experiments probing the entire expected range of this parameter, and extracting the resulting estimation in post-processing. Here we present an adaptive multi-parameter Bayesian approach, based on a simple analytical update rule, to estimate the key decoherence timescales ($T_1$, $T_2^*$ and $T_2$) and the corresponding decay exponent of a quantum system in real time, using information gained in preceding experiments. This approach reduces the time required to reach a given uncertainty by a factor up to an order of magnitude, depending on the specific experiment, compared to the standard protocol of curve fitting. A further speed-up of a factor $\sim 2$ can be realised by performing our optimisation with respect to sensitivity as opposed to variance.