Qian Xu

Qian Xu is a Sherman Fairchild Postdoctoral Scholar Research Associate at the Walter Burke Institute for Theoretical Physics, California Institute of Technology (Caltech), supervised by John Preskill. Their research focuses on quantum error correction and fault-tolerant quantum computing within Caltech's theoretical physics ecosystem.

Education:

• Ph.D. in Quantum Science and Engineering, University of Chicago (2024), advised by Liang Jiang. Thesis: 'Towards Practical Fault-Tolerant Quantum Computing'.
• B.S. in Physics, Nanjing University (2019).

Research Interests: Xu pioneers approaches to minimize space-time overhead in fault-tolerant quantum systems through novel error-correcting codes and noise-robust processor design. Their work integrates quantum error correction, quantum control, and reservoir engineering to develop practical quantum computing architectures. Key innovations include tailored codes for biased noise environments and hardware-efficient protocols for bosonic qubit systems. Current investigations span quantum LDPC codes, homological product codes, and cat qubit stabilization techniques.

Publication Trends: Xu's 12 publications (2021-2024) reveal three dominant research thrusts: (1) Low-overhead fault tolerance using quantum LDPC and homological product codes; (2) Hardware-efficient bosonic qubit systems (cat/squeezed cat codes); (3) Noise-adaptive topological code design. This work demonstrates consistent focus on reducing physical resource requirements while maintaining fault tolerance, with increasing emphasis on experimental feasibility through collaborations with quantum hardware groups.

Labs and Teams: As a member of Caltech's Walter Burke Institute for Theoretical Physics, Xu collaborates extensively with the Preskill research group and experimental teams at Harvard/MIT. Their work bridges theoretical quantum information science and near-term quantum device engineering through the Institute's cross-disciplinary framework.