团簇态量子计算中经典信号处理的一种简单方法

Fault-tolerant quantum computation with few qubits

Reliable qubits are difficult to engineer, but standard fault-tolerance schemes use seven or more physical qubits to encode each logical qubit, with still more qubits required for error correction. The large overhead makes it hard to experiment with fault-tolerance schemes with multiple encoded qubits. The 15-qubit Hamming code protects seven encoded qubits to distance three. We give fault-tolerant procedures for applying arbitrary Clifford operations on these encoded qubits, using only two extra qubits, 17 total. In particular, individual encoded qubits within the code block can be targeted. …

通过并行化高形式横向门的规范来加速魔态制备

Fast magic state preparation by gauging higher-form transversal gates in parallel

本文提出了一种通过并行化高形式横向门规范来加速魔态制备的方法，实现快速且容错的魔态制备。

Variational certification of quantum devices

One of the requirements imposed on the realistic quantum computers is to provide computation results which can be repeated and reproduced. In the situation when one needs to repeat the quantum computation procedure several times, it is crucial that the copies of the quantum devices are similar in the sense of the produced results. In this work, we describe a simple procedure based on variational quantum eigensolver which can be utilized to compare quantum devices. The procedure is developed by combining Choi-Jamiołkowski isomorphism with the variational hybrid quantum-classical procedure for m…

良型线性量子细胞自动机的一个判定过程

A decision procedure for well-formed linear quantum cellular automata

本文介绍了一种新的量子计算模型--线性量子元胞自动机。良构性是任何量子计算设备的基本属性，因为它使我们能够将观测中的配置概率定义为其振幅的平方。我们给出了一个判定线性量子元胞自动机是否良构的有效算法。如果输入自动机具有连续邻域，则算法的复杂度在计算的代数模型中为$O(n^2)$。

使用显式关联高斯基组进行原子与分子的全阶相对论计算

All-order relativistic computations for atoms and molecules using an explicitly correlated Gaussian basis

本研究提出一种基于显式关联高斯基组的多粒子无对Dirac-Coulomb-Breit哈密顿量变分求解法，可实现原子分子能量ppb级收敛，在Z=1至28的测试中发现其与领头阶微扰理论有显著差异但偏差小于量子电动力学修正。

Variational Dirac-Coulomb explicitly correlated computations for atoms and molecules

The Dirac-Coulomb equation with positive-energy projection is solved using explicitly correlated Gaussian functions. The algorithm and computational procedure aims for a parts-per-billion convergence of the energy to provide a starting point for further comparison and further developments in relation with high-resolution atomic and molecular spectroscopy. Besides a detailed discussion of the implementation of the fundamental spinor structure, permutation and point-group symmetries, various options for the positive-energy projection procedure are presented. The no-pair Dirac-Coulomb energy conv…

走向健壮的量子计算

Towards Robust Quantum Computation

量子计算是一个理论上很有前途的课题，但还没有在大规模上实现，尽管发现了容错程序来克服退相干。部分原因是，理论上适度的要求仍然提出了令人生畏的实验挑战。本论文的目标是减少健壮量子计算所需的各种资源，重点是量子纠错码和解决NMR量子计算。已经开发了各种技术，包括用于振幅阻尼的高速率量子码、用于量子纠错的宽松准则、容错门的系统构造、用于量子过程层析成像的配方、体热状态计算中的技术以及用于实现选择性耦合逻辑门的高效解耦技术。本文还对核磁共振中的量子纠错码进行了详细的实验研究。本论文澄清并扩展了先前在quant-ph/9610043、quant-ph/9704002、quant-ph/9811068、quant-ph/9904100、quant-ph/9906112、quant-ph/0002039中报告的结果。此外，还介绍了利用最大纠缠态进行量子过程层析成像的方法，并对核磁共振量子计算进行了综述。

Eliminating Intermediate Measurements in Space-Bounded Quantum Computation

A foundational result in the theory of quantum computation known as the "principle of safe storage" shows that it is always possible to take a quantum circuit and produce an equivalent circuit that makes all measurements at the end of the computation. While this procedure is time efficient, meaning that it does not introduce a large overhead in the number of gates, it uses extra ancillary qubits and so is not generally space efficient. It is quite natural to ask whether it is possible to defer measurements to the end of a quantum computation without increasing the number of ancillary qubits. W…

费米子系统动力学的矩阵计算

Matrix computations for the dynamics of fermionic systems

在最近的一系列论文中，我们已经展示了如何使用根据海森堡运动方程演化的算子来分析某些经典系统的动力学行为。特别是，我们已经表明，提高和降低运营商在此分析中发挥相关作用。我们方法的技术问题在于求解运动方程的困难，首先，运动方程是{ \em运算符值}，其次，通常是非线性的。在本文中，我们构造了一个通用的程序，显着简化处理那些系统，可以描述的费米子算子。建议的程序允许得到一个解析解，二次和更一般的汉密尔顿。