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arXiv · 2107.13129

Freedom of mixer rotation-axis improves performance in the quantum approximate optimization algorithm

L. C. G. Govia·C. Poole·M. Saffman·H. K. Krovi
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Abstract

Variational quantum algorithms such as the quantum approximate optimization algorithm (QAOA) are particularly attractive candidates for implementation on near-term quantum processors. As hardware realities such as error and qubit connectivity will constrain achievable circuit depth in the near future, new ways to achieve high-performance at low depth are of great interest. In this work, we present a modification to QAOA that adds additional variational parameters in the form of freedom of the rotation-axis in the $XY$-plane of the mixer Hamiltonian. Via numerical simulation, we show that this leads to a drastic performance improvement over standard QAOA at finding solutions to the MAXCUT problem on graphs of up to 7 qubits. Furthermore, we explore the Z-phase error mitigation properties of our modified ansatz, its performance under a realistic error model for a neutral atom quantum processor, and the class of problems it can solve in a single round.

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L. C. G. Govia, C. Poole, M. Saffman, H. K. Krovi. 2021-07-28. Freedom of mixer rotation-axis improves performance in the quantum approximate optimization algorithm. https://doi.org/10.1103/physreva.104.062428

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