首页|一种构建参数化量子线路的区块环拓扑结构

一种构建参数化量子线路的区块环拓扑结构

扫码查看
在变分量子算法中,参数化量子线路拓扑结构的选择对算法性能具有重要意义.目前已有的拓扑结构存在一些问题,如全连接拓扑结构所需量子门数量较多,环型拓扑结构的表达能力与纠缠能力略有欠缺.为了解决以上问题,本文提出了一种新型的区块环(Block-Ring,BR)拓扑结构,在保障良好性能的同时减少参数规模(即量子门数量),降低线路复杂度.在BR拓扑中,n个量子比特被等分为多个区块,每个区块包含m个量子比特,区块内部所有量子比特两两连接,区块之间采用环型结构进行连接.为了构造BR拓扑结构的参数化量子线路,设计了一种多层线路生成算法,可自动生成由单量子比特门Rx、Rz和双量子比特门CRx或CRz构成的量子线路.IBM Q模拟实验表明,相较于环型拓扑结构,无论单层、双层以及三层BR拓扑结构的表达能力和纠缠能力均有不同程度的提升;相较于拥有最高表达能力与纠缠能力的全连接拓扑结构,BR拓扑结构呈现接近的性能指标,且线路复杂度显著降低,即参数数量与双量子比特门数量均从O(n2)降低为O(mn),线路深度从O(n2)降低为O(n/m+m2).
A Block-Ring Connected Topology of Parameterized Quantum Circuits
In the variational quantum algorithm,the selection of parameterized quantum circuit topology is of great signifi-cance to the performance of the algorithm.There are some problems in the existing topology,such as the large number of quan-tum gates required by the fully connected topology,and the slight lack of the expressibility and entanglement capability of the ring topology.This paper proposes a new block-ring(BR)topology to solve the problems above,which can effectively reduce the size of parameters(i.e.the number of parameterized gates)while ensuring performance.n qubits are divided into several blocks equally,each block contains m qubits.Qubits in the block are connected in pairs,and the blocks are connected by ring structure.In order to construct parameterized quantum circuits with BR topology,we designed a algorithm of generating multiple-layer cir-cuit,which can automatically generate quantum circuits composed of single-qubit gate Rx,Rz and two-qubit gate CRx or CRz.The IBM Q simulation experiment shows that compared with the ring topology,the expressibility and entanglement capability of single-layer,double-layer and triple-layer BR topology are improved in different degrees;Compared with the all-to-all connected topology with the highest expression ability and entanglement capability,BR topology presents a close performance,and the cir-cuit complexity is significantly reduced,that is,the number of parameters and the number of double quantum gates are reduced from O(n2)to O(mn),and the circuit depth is reduced from O(n2)to O(n/m+m2).

parameterized quantum circuitscircuit topologyblock-ring topologyexpressibilityentangling capabil-itycircuit complexity

刘文杰、吴青山、查颖、王海彬

展开 >

南京信息工程大学软件学院,江苏南京 210044

南京信息工程大学江苏省大气环境与装备技术协同创新中心,江苏南京 210044

数字取证教育部工程研究中心,江苏南京 210044

参数化量子线路 线路拓扑结构 区块环拓扑 表达能力 纠缠能力 线路复杂度

国家自然科学基金科技创新2030——"量子通信与量子计算机"重大项目江苏省基础研究计划(自然科学基金)项目

620712402021ZD0302901BK20231142

2024

电子学报
中国电子学会

电子学报

CSTPCD北大核心
影响因子:1.237
ISSN:0372-2112
年,卷(期):2024.52(8)
  • 1