Hi, welcome to my page! I am a Research Scientist at Meta. Prior to this, I was a postdoctoral associate at the Department of Electrical and Computer Engineering, University of Minnesota, mentored by Prof. Mingyi Hong and Prof. Shuzhong Zhang. I obtained my Ph.D. degree in Applied Mathematics at the Department of Mathematics, UC Davis, advised by Prof. Krishna Balasubramanian and Prof. Shiqian Ma. Prior to this, I received my B.S. degree in Mathematics from Zhejiang University. My CV is here.

My research lies at the intersection of applied mathematics, optimization theory, and artificial intelligence, with a focus on developing principled algorithms that advance both theoretical foundations and practical applications in modern machine learning. Specifically, I work on:

  • Algorithm design for gradient-based, gradient-free (zeroth-order), and primal–dual methods for large-scale nonconvex optimization, including problems on Riemannian manifolds.
  • Convergence theory for deterministic and stochastic minimax and bilevel optimization, with applications to machine learning and operations research.
  • Distributed, decentralized and federated optimization algorithms for training large-scale AI systems.
  • Theoretical foundations of reinforcement learning, especially policy-based methods, and their role in aligning large language models (LLMs).
  • Efficient pre-training and fine-tuning methods for LLMs, bridging optimization principles with practical deployment.

News

  • August 2025: Starting my new job as Research Scientist at Meta!
  • February 2025: Paper Problem-Parameter-Free Decentralized Nonconvex Stochastic Optimization is accepted by Pacific Journal of Optimization.
  • January 2025: Paper Joint Demonstration and Preference Learning Improves Policy Alignment with Human Feedback is accepted by ICLR 2025 (Spotlight). Congratulations to all my collaborators!
  • January 2025: Paper Riemannian Bilevel Optimization is accepted by Journal of Machine Learning Research!
  • November 2024: Paper A Riemannian ADMM is accepted by Mathematics of Operations Research!
  • September 2024: Two papers are accepted by NeurIPS 2024. Congratulations to all my collaborators!
    • Getting More Juice Out of the SFT Data: Reward Learning from Human Demonstration Improves SFT for LLM Alignment
    • SLTrain: a sparse plus low-rank approach for parameter and memory efficient pretraining
  • August 2024: I'm very happy to receive the INFORMS Computing Society Prize!
  • August 2024: Paper Zeroth-order Riemannian Averaging Stochastic Approximation Algorithms is accepted by SIAM Journal on Optimization!
  • July 2024: A new grant Bi-Level Optimization for Hierarchical Machine Learning Problems: Models, Algorithms and Applications is awarded from NSF. I'm excited to be the co-PI of this project with Prof Hong!
  • May 2024: Paper Revisiting Zeroth-Order Optimization for Memory-Efficient LLM Fine-Tuning: A Benchmark is accepted by ICML 2024. Congratulations to all my collaborators!