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

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.

14 pages, 7 figures

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Cited by in corpus (7)

• Expressive Quantum Supervised Machine Learning using Kerr-nonlinear Parametric Oscillators
• Symmetrically Threaded Superconducting Quantum Interference Devices As Next Generation Kerr-cat Qubits
• Fast elementary gates for universal quantum computation with Kerr parametric oscillator qubits
• Residual-$ZZ$-coupling suppression and fast two-qubit gate for Kerr-cat qubits based on level-degeneracy engineering
• High-performance conditional-driving gate for Kerr parametric oscillator qubits
• Coherence-Mediated Quantum Thermometry in a Hybrid Circuit-QED Architecture
• Exact amplitudes of parametric processes in driven Josephson circuits