Control of the Z Z coupling between Kerr cat qubits via transmon couplers

作者：Takaaki Aoki, Taro Kanao, Hayato Goto, Shiro Kawabata, Shumpei Masuda · 发表于：Physical Review Applied · 年份：2024 · DOI：10.1103/physrevapplied.21.014030 · 被引用次数：14 · 研究领域：Quantum Computing Algorithms and Architecture、Quantum Information and Cryptography、Quantum and electron transport phenomena

Kerr cat qubits are a promising candidate for fault-tolerant quantum computers owing to the biased nature of their errors. The $ZZ$ coupling between the qubits can be utilized for a two-qubit entangling gate, but the residual coupling called $ZZ$ crosstalk is detrimental to precise computing. In order to resolve this problem, we propose a tunable $ZZ$-coupling scheme using two transmon couplers. By setting the detunings of the two couplers at opposite values, the residual $ZZ$ couplings via the two couplers cancel each other out. We also apply our scheme to the ${R}_{ZZ}(\mathrm{\ensuremath{\Theta}})$ gate ($ZZ$ rotation with angle $\mathrm{\ensuremath{\Theta}}$), one of the two-qubit entangling gates. We numerically show that the fidelity of the ${R}_{ZZ}(\ensuremath{-}\ensuremath{\pi}/2)$ gate is higher than 99.9% in a case of 16-ns gate time and without decoherence.