论文标题
展开SVT以获得N Qubit量子层析成像的计算高效SVT
Unrolling SVT to obtain computationally efficient SVT for n-qubit quantum state tomography
论文作者
论文摘要
量子状态层析成像旨在估计量子机械系统的状态,该系统由痕量遗传者正阳性半限体复合物矩阵描述,并给定一组状态测量。现有的作品着重于使用压缩传感方法估算代表状态的密度矩阵,其测量值仅比层析成分所需的测量值少,并假设真实状态具有较低的等级。估计状态的一种非常流行的方法是使用奇异值阈值(SVT)算法。在这项工作中,我们提出了一种机器学习方法,通过展开SVT的迭代,以估算N Qubit Systems的量子状态,我们称之为学习的量子状态层析成像(LQST)。由于仅展开的SVT可能无法确保网络的输出符合量子状态所需的约束,因此我们设计和训练一个自定义神经网络,其体系结构的灵感来自SVT的迭代,并具有其他层,以满足所需的约束。我们表明,我们提出的LQST很少有层与SVT算法相比,其保真度要好得多,而SVT算法需要数百个迭代才能收敛。我们还通过信息不完整的嘈杂测量值来证明量子钟状状态的重建。
Quantum state tomography aims to estimate the state of a quantum mechanical system which is described by a trace one, Hermitian positive semidefinite complex matrix, given a set of measurements of the state. Existing works focus on estimating the density matrix that represents the state, using a compressive sensing approach, with only fewer measurements than that required for a tomographically complete set, with the assumption that the true state has a low rank. One very popular method to estimate the state is the use of the Singular Value Thresholding (SVT) algorithm. In this work, we present a machine learning approach to estimate the quantum state of n-qubit systems by unrolling the iterations of SVT which we call Learned Quantum State Tomography (LQST). As merely unrolling SVT may not ensure that the output of the network meets the constraints required for a quantum state, we design and train a custom neural network whose architecture is inspired from the iterations of SVT with additional layers to meet the required constraints. We show that our proposed LQST with very few layers reconstructs the density matrix with much better fidelity than the SVT algorithm which takes many hundreds of iterations to converge. We also demonstrate the reconstruction of the quantum Bell state from an informationally incomplete set of noisy measurements.