The fermionic SWAP network is a qubit routing sequence that can be used to efficiently execute the Quantum Approximate Optimization Algorithm (QAOA). Even with a minimally-connected topology on an n-qubit processor, this routing sequence enables O(n^2) operations to execute in O(n) steps. In this work, we optimize the execution of fermionic SWAP networks for QAOA through two techniques. First, we take advantage of an overcomplete set of native hardware operations [including 150 ns controlled-pi/2 phase gates with up to 99.67(1)% fidelity] in order to decompose the relevant quantum gates and SWAP networks in a manner which minimizes circuit depth and maximizes gate cancellation. Second, we introduce Equivalent Circuit Averaging, which randomizes over degrees of freedom in the quantum circuit compilation to reduce the impact of systematic coherent errors. Our techniques are experimentally validated on the Advanced Quantum Testbed through the execution of QAOA circuits for finding the ground state of two- and four-node Sherrington-Kirkpatrick spin-glass models with various randomly sampled parameters. We observe a ~60% average reduction in error (total variation distance) for QAOA of depth p = 1 on four transmon qubits on a superconducting quantum processor.
Optimizing QAOA circuit transpilation with parity twine and SWAP network encodings
Jülich Supercomputing Centre, Institute for Advanced Simulation, Forschungszentrum Jülich（于利希研究中心先进模拟研究所超级计算中心）；Institute for Quantum Computing Analytics (PGI-12), Forschungszentrum Jülich（于利希研究中心量子计算分析研究所）；Department of Mechanical Engineering, Virginia Tech（弗吉尼亚理工大学机械工程系）；Davidson School of Chemical Engineering, Purdue University（普渡大学戴维森化学工程学院）；AIDAS；RWTH Aachen University（亚琛工业大学）
Beyond Quantum Advantage: Improved Classical Algorithms for the Binary Paint Shop Problem
Institute for Frontier Materials on Earth and in Space, German Aerospace Center (DLR)（地球与太空前沿材料研究所，德国航空航天中心）；University of Cologne（科隆大学）；Institute for Software Technology, Department High-Performance Computing, German Aerospace Center (DLR)（高性能计算系软件工程研究所，德国航空航天中心）
Classical and Quantum Heuristics for the Binary Paint Shop Problem
Centre for Quantum Technologies (CQT), National University of Singapore（新加坡国立大学量子技术中心）；Quantum Innovation Centre (Q.InC), Agency for Science, Technology and Research (A*STAR)（科技研究局量子创新中心）；Department of Quantum Science and Technology, Research School of Physics, Australian National University（澳大利亚国立大学物理研究学院量子科学与技术系）；Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR)（科技研究局高性能计算研究所）；Science, Mathematics and Technology Cluster, Singapore University of Technology and Design（新加坡科技设计大学科学技术与数学集群）；Engineering Cluster, Singapore Institute of Technology（新加坡理工学院工程集群）
From Circuits to Hardware: Benchmarking Standard and Qubit-Efficient Quantum Optimization on Real Hardware
School of Computing and Information Systems, Singapore Management University（新加坡管理大学计算与信息系）；Institute of High Performance Computing, A*STAR（A*STAR高性能计算研究所）
