Fast CZ Gate via Energy-Level Engineering in Superconducting Qubits with a Tunable Coupler

• URL: http://arxiv.org/abs/2510.09461v2
• Date: Tue, 14 Oct 2025 11:48:02 GMT
• Title: Fast CZ Gate via Energy-Level Engineering in Superconducting Qubits with a Tunable Coupler
• Authors: Benzheng Yuan, Chaojie Zhang, Chuanbing Han, Shuya Wang, Peng Xu, Huihui Sun, Qing Mu, Lixin Wang, Bo Zhao, Weilong Wang, Zheng Shan,
• Abstract summary: We propose a scheme for rapid controlled-Z (CZ) gate implementation through energy-level engineering.<n> Numerical simulations achieved a 17 ns nonadiabatic CZ gate with fidelity over 99.99%.
• Score: 8.381205219457184
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: In superconducting quantum circuits, decoherence errors in qubits constitute a critical factor limiting quantum gate performance. To mitigate decoherence-induced gate infidelity, rapid implementation of quantum gates is essential. Here we propose a scheme for rapid controlled-Z (CZ) gate implementation through energy-level engineering, which leverages Rabi oscillations between the |11> state and the superposition state in a tunable-coupler architecture. Numerical simulations achieved a 17 ns nonadiabatic CZ gate with fidelity over 99.99%. We further investigated the performance of the CZ gate in the presence of anharmonicity offsets. The results demonstrate that a high-fidelity CZ gate with an error rate below 10^-4 remains achievable even with finite anharmonicity variations. Furthermore, the detrimental impact of spectator qubits in different quantum states on the fidelity of CZ gate is effectively suppressed by incorporating a tunable coupler. This scheme exhibits potential for extending the circuit execution depth constrained by coherence time limitations.

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