Chang-Ling Zou

Volcano Architecture for Scalable Quantum Processor Units

Dong-Qi Ma [1,2,3], Qing-Xuan Jie [1,2,3], Ya-Dong Hu [1,2,3], Wen-Yi Zhu [1,2,3], Yi-Chen Zhang [1,2,3], Hong-Jie Fan [1,2,3], Xiao-Kang Zhong [1,2,3], Guang-Jie Chen [1,2,3], Yan-Lei Zhang [1,2,3], Tian-Yang Zhang [1,2,3], Xi-Feng Ren [1,2,3,4], Liang Chen [1,2,3], Zhu-Bo Wang [1,2,3], Guang-Can Guo [1,2,3,4], Chang-Ling Zou [1,2,3,4]

Abstract

Quantum information processing platforms based on array of matter qubits, such as neutral atoms, trapped ions, and quantum dots, face significant challenges in scalable addressing and readout as system sizes increase. Here, we propose the "Volcano" architecture that establishes a new quantum processing unit implementation method based on optical channel mapping on a arbitrarily arranged static qubit array. To support the feasibility of Volcano architecture, we show a proof-of-principle demonstration by employing a photonic chip that leverages custom-designed three-dimensional waveguide structures to transform one-dimensional beam arrays into arbitrary two-dimensional output patterns matching qubit array geometries. We demonstrate parallel and independent control of 49-channel with negligible crosstalk and high uniformity. This architecture addresses the challenges in scaling up quantum processors, including both the classical link for parallel qubit control and the quantum link for efficient photon collection, and holds the potential for interfacing with neutral atom arrays and trapped ion crystals, as well as networking of heterogeneous quantum systems.

Beating the break-even point with autonomous quantum error correction

Yi Li [1,2,5,6], Qingyuan Mei [1,2], Qing-Xuan Jie [3,4], Weizhou Cai [3,4], Yue Li [1,2], Zhiyuan Liu [1,2], Zi-Jie Chen [3,4], Zihan Xie [1,2,6], Xu Cheng [1,2,6], Xingyu Zhao [1,2,6], Zhenghao Luo [1,2], Mengxiang Zhang [7], Xu-Bo Zou [3,4], Chang-Ling Zou [3,4,6], Yiheng Lin [1,2,6], Jiangfeng Du [1,2,6,8]

Abstract

Quantum error correction (QEC) is essential for practical quantum computing, as it protects fragile quantum information from errors by encoding it in high-dimensional Hilbert spaces. Conventional QEC protocols typically require repeated syndrome measurements, real-time feedback, and the use of multiple physical qubits for encoding. Such implementations pose significant technical complexities, particularly for trapped-ion systems, with high demands on precision and scalability. Here, we realize autonomous QEC with a logical qubit encoded in multiple internal spin states of a single trapped ion, surpassing the break-even point for qubit lifetime. Our approach leverages engineered spin-motion couplings to transfer error-induced entropy into motional modes, which are subsequently dissipated through sympathetic cooling with an ancilla ion, fully eliminating the need for measurement and feedback. By repetitively applying this autonomous QEC protocol under injected low-frequency noise, we extend the logical qubit lifetime to approximately 11.6 ms, substantially outperforming lifetime for both the physical qubit ($\simeq$0.9 ms) and the uncorrected logical qubit ($\simeq$0.8 ms), thereby beating the break-even point with autonomous protection of quantum information without measurement or post-selection. This work presents an efficient approach to fault-tolerant quantum computing that harnesses the intrinsic multi-level structure of trapped ions, providing a distinctive path toward scalable architectures and robust quantum memories with reduced overhead.