A team of physicists led by Prof. Luming Duan from Tsinghua University has developed a new approach of realizing coherently convertible dual-type qubits with the same ion species. The work is described in a paper published in the journal Nature Physics and marks a significant step in large-scale quantum computing and networking.

Trapped ions constitute one of the most promising systems for implementing quantum computing and networking. For large-scale ion-trap-based quantum computers and networks, it is critical to have two types of qubit: one for computation and storage, and another for auxiliary operations such as qubit detection, sympathetic cooling and entanglement generation through photon links. Previously, it was assumed that the dual-type ion qubits must be implemented in hybrid systems of two ion species. However, it is challenging to control the fraction and the positioning of each qubit type in many-ion crystals. The researchers resolve these challenges by implementing two coherently convertible qubit types using one ion species, and have demonstrated dynamic conversion between two types of qubit. This work is also introduced by Prof. Hempel from ETH in News & Views of Nature Physics, who regarded that “the addition of this method for coherent conversion to the quantum information toolbox marks a clear advance for the field”.

The corresponding author of the paper is Professor Luming Duan, and co-first authors are IIIS postdoc Haoxiang Yang, and IIIS PhD student Jianyu Ma. Other co-authors include IIIS Assistant Professor Yukai Wu, IIIS PhD students Ye Wang, Mingming Cao, Weixuan Guo, Lu Feng, IIIS Assistant Researcher Yuanyuan Huang and Associate Researcher Zichao Zhou. This work was supported by Tsinghua University Initiative Scientific Research Program and the Ministry of Education of China through its fund to IIIS.

The full paper is available at: https://doi.org/10.1038/s41567-022-01661-5