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arXiv · 2203.04984

Circuit connectivity boosts by quantum-classical-quantum interfaces

Roeland Wiersema·Leonardo Guerini·Juan Felipe Carrasquilla·Leandro Aolita
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Abstract

High-connectivity circuits are a major roadblock for current quantum hardware. We propose a hybrid classical-quantum algorithm to simulate such circuits without swap-gate ladders. As main technical tool, we introduce quantum-classical-quantum interfaces. These replace an experimentally problematic gate (e.g. a long-range one) by single-qubit random measurements followed by state-preparations sampled according to a classical quasi-probability simulation of the noiseless gate. Each interface introduces a multiplicative statistical overhead which is remarkably independent of the on-chip qubit distance. Hence, by applying interfaces to the longest range gates in a target circuit, significant reductions in circuit depth and gate infidelity can be attained. We numerically show the efficacy of our method for a Bell-state circuit for two increasingly distant qubits and a variational ground-state solver for the transverse-field Ising model on a ring. Our findings provide a versatile toolbox for error-mitigation and circuit boosts tailored for noisy, intermediate-scale quantum computation.

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Roeland Wiersema, Leonardo Guerini, Juan Felipe Carrasquilla, Leandro Aolita. 2022-03-09. Circuit connectivity boosts by quantum-classical-quantum interfaces. https://doi.org/10.1103/physrevresearch.4.043221

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