高效地找到最佳流量

Finding the optimal cluster state configuration. Minimization of one-way quantum computation errors

In this paper, we estimate the errors of Gaussian transformations implemented using one-way quantum computations on cluster states of various configurations. From all possible cluster state configurations, we choose those that give the smallest computation error. Furthermore, we evaluate errors in hybrid computational schemes, in which Gaussian operations are performed using one-way computations with additional linear transformations. As a result, we find the optimal strategy for the implementation of universal Gaussian computations with minimal errors.

使用Ising机在化学反应网络中寻找最优路径

Finding Optimal Pathways in Chemical Reaction Networks Using Ising Machines

针对化学反应网络最优路径寻找的组合优化难题，首次提出基于Ising机的求解方案，结合贝叶斯优化与惩罚项分组调优技术，实验验证了近似最优路径求解的可行性。

求解量子最优控制的D-MORPH方法的改进

An improvement of D-MORPH method for finding quantum optimal control

研究了寻找量子系统最优控制的著名算法D-MORPH，以实现量子系统在最后时刻的幺正演化，并给出了该算法各阶修正的新的数学表达式，其中包含了系统哈密顿量的修正子信息.包括这样的校正导致以高精度进行更快的最优量子控制的搜索，即，允许节省计算资源。

关于在单次运行阶寻找算法中高效地对任意整数进行完全因式分解

On completely factoring any integer efficiently in a single run of an order finding algorithm

本文证明对于任意整数 $N$，给定从 $\mathbb Z_N^*$ 中均匀随机选取的单个元素的阶，能以极高概率在多项式时间内高效找到 $N$ 的完全因式分解，这意味着通常单次运行 Shor 算法的量子部分即可，随后通过经典后处理以极低成本恢复所有素因子。

Finding optimal Bell inequalities using the cone-projection technique

Bell inequalities are relevant for many problems in quantum information science, but finding them for many particles is computationally hard. Recently, a computationally feasible method called cone-projection technique has been developed to find all optimal Bell inequalities under some constraints, which may be given by some symmetry or other linear conditions. In this paper we extend this work in several directions. We use the method to generalize the I4422 inequality to three particles and a so-called GYNI inequality to four particles. Additionally, we find Bell inequalities for three partic…

Collision models can efficiently simulate any multipartite Markovian quantum dynamics

We introduce the multipartite collision model, defined in terms of elementary interactions between subsystems and ancillae, and show that it can simulate the Markovian dynamics of any multipartite open quantum system. We develop a method to estimate an analytical error bound for any repeated interactions model, and we use it to prove that the error of our scheme displays an optimal scaling. Finally, we provide a simple decomposition of the multipartite collision model into elementary quantum gates, and show that it is efficiently simulable on a quantum computer according to the dissipative qua…

寻找量子生成对抗网络的最优训练参数

Finding Optimal Training Parameters for Quantum Generative Adversarial Networks

本文研究Qiskit风格参数化电路QGAN框架中的最优训练参数，以提升量子生成对抗网络将经典数据加载到量子态的性能。

Finding efficient observable operators in entanglement detection via convolutional neural network

In quantum information, it is of high importance to efficiently detect entanglement. Generally, it needs quantum tomography to obtain state density matrix. However, it would consumes a lot of measurement resources, and the key is how to reduce the consumption. In this paper, we discovered the relationship between convolutional layer of artificial neural network and the average value of an observable operator in quantum mechanics. Then we devise a branching convolutional neural network which can be applied to detect entanglement in 2-qubit quantum system. Here, we detect the entanglement of Wer…

量子最优控制的信息论分析

An information theoretical analysis of quantum optimal control

我们表明，如果一个有效的经典表示的动力学存在，多体量子系统的最优控制问题可以有效地解决有限精度。我们表明，解决量子最优控制问题所需的参数空间的大小定义在纯，混合状态和幺正多项式有界的可达状态的集合的大小在多项式时间。我们提供了一个界的最小时间进行最佳的过程中给定的控制脉冲的带宽，这是连续版本的Solovay-Kitaev定理。我们探讨了系统中存在的纠缠和控制问题的复杂性之间的联系，表明一维轻微纠缠动力学可以有效地控制。最后，我们量化噪声如何影响所呈现的结果。

Quantum states cannot be transmitted efficiently classically

We show that any classical two-way communication protocol with shared randomness that can approximately simulate the result of applying an arbitrary measurement (held by one party) to a quantum state of $n$ qubits (held by another), up to constant accuracy, must transmit at least $Ω(2^n)$ bits. This lower bound is optimal and matches the complexity of a simple protocol based on discretisation using an $ε$-net. The proof is based on a lower bound on the classical communication complexity of a distributed variant of the Fourier sampling problem. We obtain two optimal quantum-classical separation…

Finding the optimal Nash equilibrium in a discrete Rosenthal congestion game using the Quantum Alternating Operator Ansatz

This paper establishes the tractability of finding the optimal Nash equilibrium, as well as the optimal social solution, to a discrete congestion game using a gate-model quantum computer. The game is of the type originally posited by Rosenthal in the 1970's. To find the optimal Nash equilibrium, we formulate an optimization problem encoding based on potential functions and path selection constraints, and solve it using the Quantum Alternating Operator Ansatz. We compare this formulation to its predecessor, the Quantum Approximate Optimization Algorithm. We implement our solution on an idealize…

Hardness of efficiently generating ground states in postselected quantum computation

Generating ground states of any local Hamiltonians seems to be impossible in quantum polynomial time. In this paper, we give evidence for the impossibility by applying an argument used in the quantum-computational-supremacy approach. More precisely, we show that if ground states of any $3$-local Hamiltonians can be approximately generated in quantum polynomial time with postselection, then ${\sf PP}={\sf PSPACE}$. Our result is superior to the existing findings in the sense that we reduce the impossibility to an unlikely relation between classical complexity classes. We also discuss what makes…