Reservoir Computing Approach to Quantum State Measurement
Reservoir Computing Approach to Quantum State Measurement
复制标题
量子态测量的储层计算方法
作者：
Gerasimos Angelatos;S. Khan;H. Türeci
快速、准确的量子态测量对于最大化从量子系统中提取的信息具有重要意义。它的优化对于部署在NISQ时代的量子算法、量子模拟器以及量子计算的容错变体的多量子比特量子处理器来说尤其关键。在这里，我们提出了一种基于硬件的库计算方案，用于超导多量子比特系统的量子态读出。我们考虑了一个由约瑟夫森参数振荡器实现的小型克尔振荡器网络，该网络可以用最小的器件开销实现，并且与被测量子系统在同一平台上实现。我们从理论上分析了它作为存储计算机对符合量子统计特征的随机时变信号进行分类的能力。然后，我们将该克尔网络储存库计算机应用于联合多量子比特读出。我们展示了这些测量轨迹的快速多项式分类，其保真度超过了传统的过滤方法。这种储层计算框架避免了神经网络的计算代价高昂的训练标准。我们强调了这一点，与最先进的过滤方法相比，在两个量子比特的联合色散读出任务中，训练成本降低了超过一个数量级，实现了理论上的最佳保真度。我们的结果表明，未经优化的Kerr网络水库计算机可以在计算边缘作为低延迟模拟处理器运行，并提供快速和健壮的量子态测量处理。
Rapid and accurate quantum state measurement is important for maximizing the extracted information from a quantum system. Its optimization plays a critical role in particular for multi-qubit quantum processors deployed for NISQ-era quantum algorithms, quantum simulators, as well as a fault-tolerant variant of quantum computation. Here we propose reservoir computing as a hardware-based solution to quantum state readout of superconducting multi-qubit systems. We consider a small network of Kerr oscillators realized by Josephson parametric oscillators, which can be implemented with minimal device overhead and in the same platform as the measured quantum system. We theoretically analyze its ability to operate as a reservoir computer to classify stochastic time-dependent signals subject to quantum statistical features. We then apply this Kerr network reservoir computer to joint multi-qubit readout. We demonstrate rapid multinomial classification of these measurement trajectories with a fidelity exceeding that of conventional filtering approaches. This reservoir computing framework avoids computationally expensive training standard for neural-networks. We highlight this by showing more than an order of magnitude reduction in training cost to achieve theoretically optimal fidelity on a two-qubit joint dispersive readout task, when compared with state-of-the-art filtering approaches. Our results indicate that an unoptimized Kerr network reservoir computer can operate as a low latency analog processor at the computational edge and provide rapid and robust processing of quantum state measurement.