An error-protected cross-resonance switch in weakly-tuneable architectures

Xu, Xuexin; Ansari, M.

doi:10.48550/ARXIV.2212.05519

Preprint

FZJ-2023-01038

An error-protected cross-resonance switch in weakly-tuneable architectures

Xu, X.FZJ* ; Ansari, M.FZJ*

2022
arXiv

arXiv (2022) [10.48550/ARXIV.2212.05519]

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Please use a persistent id in citations: http://hdl.handle.net/2128/33801 doi:10.48550/ARXIV.2212.05519

Abstract: In two-qubit gates activated by microwave pulses, by turning pulse on or off, the state of qubits are swapped between entangled or idle modes. In either mode, the presence of stray couplings makes qubits accumulate coherent phase error. However, the error rates in the two modes differ because qubits carry different stray coupling strengths in each mode; therefore, eliminating stray coupling from one mode does not remove it from the other. We propose to combine such a gate with a tunable coupler and show that both idle and entangled qubits can become free from stray couplings. This significantly increases the operational switch fidelity in quantum algorithms. We further propose a weakly-tunable qubit as an optimum coupler to bring the two modes parametrically near each other. This remarkably enhances the tuning process by reducing its leakage.

Keyword(s): Quantum Physics (quant-ph) ; FOS: Physical sciences

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