Direct Implementation of High-Fidelity Three-Qubit Gates for Superconducting Processor with Tunable Couplers

Abstract

Three-qubit gates can be constructed using combinations of single-qubit and two-qubit gates, making their independent realization unnecessary. However, direct implementation of three-qubit gates reduces the depth of quantum circuits, streamlines quantum programming, and facilitates efficient circuit optimization, thereby enhancing overall performance in quantum computation. In this work, we propose and experimentally demonstrate a high-fidelity scheme for implementing a three-qubit controlled-controlled-Z (CCZ) gate in a flip-chip superconducting quantum processor with tunable couplers. This direct CCZ gate is implemented by simultaneously leveraging two tunable couplers interspersed between three qubits to enable three-qubit interactions, achieving an average final state fidelity of $97.94\%$ and a process fidelity of $93.54\%$. This high fidelity cannot be achieved through a simple combination of single- and two-qubit gate sequences from processors with similar performance levels. Our experiments also verify that multilayer direct implementation of the CCZ gate exhibits lower leakage compared to decomposed gate approaches. As a showcase, we utilize the CCZ gate as an oracle to implement the Grover search algorithm on three qubits, demonstrating high performance with the target probability amplitude significantly enhanced after two iterations. These results highlight the advantage of our approach, and facilitate the implementation of complex quantum circuits.

main text: 8 pages, 4 figures; supp: 15 pages, 13 figures, 2 tables

References in corpus (47)

• Quantum Computing in the NISQ era and beyond
• Supplementary information for "Quantum supremacy using a programmable superconducting processor"
• Quantum Mechanics helps in searching for a needle in a haystack
• Elementary gates for quantum computation
• Suppressing quantum errors by scaling a surface code logical qubit
• Logical quantum processor based on reconfigurable atom arrays
• Quantum error correction below the surface code threshold
• Realization of Three-Qubit Quantum Error Correction with Superconducting Circuits
• Efficient Z-Gates for Quantum Computing
• Realization of the quantum Toffoli gate with trapped ions
• Realization of high-fidelity CZ and ZZ-free iSWAP gates with a tunable coupler
• Universal fault-tolerant quantum computation with only transversal gates and error correction
• Complete 3-Qubit Grover Search on a Programmable Quantum Computer
• High-fidelity, high-scalability two-qubit gate scheme for superconducting qubits
• On the advantages of using relative phase Toffolis with an application to multiple control Toffoli optimization
• Implementation of Conditional-Phase Gates based on tunable ZZ-Interactions
• High-Fidelity, Frequency-Flexible Two-Qubit Fluxonium Gates with a Transmon Coupler
• High fidelity two-qubit gates on fluxoniums using a tunable coupler
• Diabatic gates for frequency-tunable superconducting qubits
• Tunable coupler for realizing a controlled-phase gate with dynamically decoupled regime in a superconducting circuit
• High-fidelity three-qubit iToffoli gate for fixed-frequency superconducting qubits
• Continuous-variable geometric phase and its manipulation for quantum computation in a superconducting circuit
• Five Two-Qubit Gates Are Necessary for Implementing Toffoli Gate
• Single-step implementation of high fidelity $n$-bit Toffoli gate
• Quantum gate learning in engineered qubit networks: Toffoli gate with always-on interactions
• Universal fault-tolerant gates on concatenated stabilizer codes
• Universal fidelity reduction of quantum operations from weak dissipation
• Realization of efficient quantum gates with a superconducting qubit-qutrit circuit
• Programmable Heisenberg interactions between Floquet qubits
• Fast multi-qubit gates through simultaneous two-qubit gates
• Suppression of static ZZ interaction in an all-transmon quantum processor
• A programmable three-qubit superconducting processor with all-to-all connectivity
• Extensive characterization of a family of efficient three-qubit gates at the coherence limit
• Protocol for a resonantly-driven three-qubit Toffoli gate with silicon spin qubits
• Demonstration of tunable three-body interactions between superconducting qubits
• Empowering high-dimensional quantum computing by traversing the dual bosonic ladder
• Realization of high-fidelity CZ gates in extensible superconducting qubits design with a tunable coupler
• Controlled-Controlled-Phase Gates for Superconducting Qubits Mediated by a Shared Tunable Coupler
• Single Shot i-Toffoli Gate in Dispersively Coupled Superconducting Qubits
• Native three-body interaction in superconducting circuits
• Shallow unitary decompositions of quantum Fredkin and Toffoli gates for connectivity-aware equivalent circuit averaging
• Realisation of adiabatic and diabatic CZ gates in superconducting qubits coupled with a tunable coupler
• Impact of decoherence on the fidelity of quantum gates leaving the computational subspace
• High-precision pulse calibration of tunable couplers for high-fidelity two-qubit gates in superconducting quantum processors
• Machine-learning based three-qubit gate for realization of a Toffoli gate with cQED-based transmon systems
• Polarization and Orbital Angular Momentum Encoded Quantum Toffoli Gate Enabled by Diffractive Neural Networks
• Analyzing the Toffoli gate in disordered circuit QED

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