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arXiv · 2307.14130

Quasiparticle Dynamics in Superconducting Quantum-Classical Hybrid Circuits

Kuang Liu·Xiaoliang He·Zhengqi Niu·Hang Xue·Wenbing Jiang·Liliang Ying·Wei Peng·Masaaki Maezawa·Zhirong Lin·Xiaoming Xie·Zhen Wang
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Abstract

Single flux quantum (SFQ) circuitry is a promising candidate for a scalable and integratable cryogenic quantum control system. However, the operation of SFQ circuits introduces non-equilibrium quasiparticles (QPs), which are a significant source of qubit decoherence. In this study, we investigate QP behavior in a superconducting quantum-classical hybrid chip that comprises an SFQ circuit and a qubit circuit. By monitoring qubit relaxation time, we explore the dynamics of SFQ-circuit-induced QPs. Our findings reveal that the QP density near the qubit reaches its peak after several microseconds of SFQ circuit operation, which corresponds to the phonon-mediated propagation time of QPs in the hybrid circuits. This suggests that phonon-mediated propagation dominates the spreading of QPs in the hybrid circuits. Our results lay the foundation to suppress QP poisoning in quantum-classical hybrid systems.

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Kuang Liu, Xiaoliang He, Zhengqi Niu, Hang Xue, Wenbing Jiang, Liliang Ying, Wei Peng, Masaaki Maezawa, Zhirong Lin, Xiaoming Xie, Zhen Wang. 2023-07-26. Quasiparticle Dynamics in Superconducting Quantum-Classical Hybrid Circuits. https://doi.org/10.1103/physrevb.108.064512

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