Control of the $ZZ$ coupling between Kerr-cat qubits via transmon couplers

• URL: http://arxiv.org/abs/2303.16622v4
• Date: Mon, 22 Jan 2024 07:53:45 GMT
• Title: Control of the $ZZ$ coupling between Kerr-cat qubits via transmon couplers
• Authors: Takaaki Aoki, Taro Kanao, Hayato Goto, Shiro Kawabata, and Shumpei Masuda
• Abstract summary: Kerr-cat qubits are a promising candidate for fault-tolerant quantum computers. We propose a $ZZ$-coupling scheme using two transmon couplers. We numerically show that the fidelity of the $R_zz(-pi/2)$ gate is higher than 99.9% in a case of $16$-ns gate time and without decoherence.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: 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 $R_{zz}(\Theta)$ gate ($ZZ$ rotation with angle $\Theta$), one of the two-qubit entangling gates. We numerically show that the fidelity of the $R_{zz}(-\pi/2)$ gate is higher than 99.9% in a case of $16$-ns gate time and without decoherence.

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