Scientists at the RIKEN Center for Quantum Computing and Toshiba have made a breakthrough in quantum computing technology by developing a quantum computer gate using a double-transmon coupler (DTC). This innovation has led to a significant improvement in the fidelity of quantum gates.
The team achieved an impressive 99.92% fidelity for a two-qubit CZ gate and an even higher 99.98% fidelity for a single-qubit gate. This advancement, part of the Q-LEAP project, is a major step towards enhancing the performance of current noisy intermediate-scale quantum (NISQ) devices and moving closer to fault-tolerant quantum computation with effective error correction.
The DTC, a novel tunable coupler, addresses various challenges in connecting qubits with high fidelity, suppressing noise, and enabling rapid, high-fidelity gate operations even with detuned qubits.
A significant aspect of this research is the use of reinforcement learning to design a quantum gate using cutting-edge fabrication techniques. This machine learning approach enabled the researchers to transform the theoretical potential of the double-transmon coupler (DTC) into a practical application. By optimizing the balance between leakage and decoherence errors, the team determined the ideal gate length of 48 nanoseconds, achieving some of the highest fidelity levels reported in the field.
Yasunobu Nakamura, director of the RIKEN Center for Quantum Computing, emphasized the importance of reducing error rates in quantum gates to enable more reliable and accurate quantum computations. He stated, “This breakthrough is crucial for the development of fault-tolerant quantum computers, which represent the future of quantum computing.”
He also highlighted the versatility of the DTC device, noting its ability to perform effectively with highly detuned qubits, making it a competitive building block for various quantum computing architectures. This adaptability ensures its integration into existing and future superconducting quantum processors, enhancing overall performance and scalability. The team aims to further reduce the gate length in the future to minimize incoherent errors.
Journal Reference:
- Rui Li, Kentaro Kubo, Yinghao Ho, Zhiguang Yan et al. Realization of High-Fidelity CZ Gate Based on a Double-Transmon Coupler. Physical Review X. DOI: 10.1103/PhysRevX.14.041050
