About Me

Hi, I am Xu Wan (万旭). I am currently a researcher in the ByteDance Seed Team. I received my Ph.D. at Zhejiang University in June 2026 advised by Prof. Mingyang Sun. I was previously a visiting student at the IDEAL Lab, Peking University. During my Ph.D., I interned at Tencent Hunyuan, ByteDance Seed, Alibaba DAMO Academy, and NetEase Fuxi AI Lab, and had the pleasure of collaborating with Prof. Wotao Yin, Dr. Speed Zhu, Dr. Sheng Chen, Dr. Yujing Hu, and many other outstanding researchers.

I am actively seeking academic collaborations. Please feel free to .

My research interests include:

Robot Use Agent

Coming soon

Beyond research, I am passionate about fitness and enjoy running and strength training. You can follow my training journey on my Strava profile. I am also enthusiastic about trail running and hiking.

Training log

View on Strava
— active days — activities — running sessions — strength sessions — hours — km

News

  • 2026.09:  🎉🎉 One paper about training-inference mismatch in LLMs got accepted at NeurIPS 2026 (co-first author)!!
  • 2026.05:  🎉🎉 Three papers about LLM Token Allocation / LLM for Optimization / T2I RL post-train got accepted at ICML 2026!
  • 2026.03:  🎉🎉 One paper about Length Penalty of LLM got accepted at ACL 2026 (co-first author)!
  • 2026.01:  🎉🎉 One paper about Off-policy LLM-RL post-train got accepted at ICLR 2026 (first author)!
  • 2025.09:  🎉🎉 One paper about robust safe RL got accepted at NeurIPS 2025 (first author)!
  • 2025.07:  🎉🎉 I was supported by the CIE-Tencent Doctoral Research Incentive Project (with only 23 recipients nationwide and a research fund of 100,000 RMB)!
  • 2025.05:  🎉🎉 One paper about elastic cloud service got accepted at SIGKDD 2025 (co-first author)!
  • 2025.05:  🎉🎉 One paper about LLM and RL colloboratation got accepted at ICML 2025 (first author)!
  • 2024.12:  🎉🎉 One paper about multi-agent RL got accepted as an oral presentation at AAAI 2025 (first author)!

Publications

Spotlight Publications

arXiv 2026
LSD reduces response-length growth and the length-scaling tax on easy queries compared with RL.

Mitigating the Length-Scaling Tax with Online Distillation

Xu Wan, Wenyue Xu, Shengjie Zhao, Mingyang Sun

  • Length Self-Distillation (LSD) reduces unnecessary response-length growth on easy queries during language model RL post-training.
ICLR 2026
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Buffer Matters: Unleashing the Power of Off-Policy Reinforcement Learning in Large Language Model Reasoning [Code]

Xu Wan, Yansheng Wang, Wenqi Huang, Mingyang Sun

  • BAPO is an off-policy RLVR framework to improve the data efficiency in large language models post-training.
ICML 2026
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The Shadow Price of Reasoning: Economic Perspective on Optimal Budget Allocation for LLMs [Code]

Xu Wan, SpeedZhu, Jiawei Cai, Guang Chen, Ximing Huang, Wiggin Zhou, Mingyang Sun

  • CLEAR implements a Lambert W policy to execute strategic abandonment, sacrificing insolvent tasks to redistribute critical computational resources to solvable complex queries.
ACL 2026
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AdapThink: Adaptive Thinking Preferences for Reasoning Language Model [Code]

Xu Wan*(co-first author), Wenyue Xu*, Wei Wang, Wotao Yin, Wenqi Huang, Shengjie Zhao, Mingyang Sun

  • AdapThink is an adaptive length penalty method for efficient thinking of reasoning language models.
ICML 2025
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Think Twice, Act Once: A Co-Evolution Framework of LLM and RL for Large-Scale Decision Making

Xu Wan, Wenyue Xu, Chao Yang, Mingyang Sun

  • Agents Co-Evolution (ACE) is a synergistic framework between LLMs and RL agents for large-scale decision-making scenarios.
ICML 2026
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ProOPF: Benchmarking and Improving LLMs for Professional-Grade Power Systems Optimization Modeling [Code]

Chao Shen, Zihan Guo, Xu Wan*(co-first author), Zhenghao Yang, Yifan Zhang, Wengi Huang, Jie Song, Zongyan Zhang, Mingyang Sun

  • ProOPF introduces a 12K-instance dataset and a 121-case expert benchmark for evaluating and improving LLMs on professional-grade optimal power flow modeling from natural language.
NeurIPS 2025
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Fuz-RL: A Fuzzy-Guided Robust Framework for Safe Reinforcement Learning under Uncertainty [Code]

Xu Wan, Chao Yang, Cheng Yang, Jie Song, Mingyang Sun

  • Fuz-RL is a novel fuzzy-guided robust framework for safe RL.
AAAI 2025
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SrSv: Integrating Sequential Rollouts with Sequential Value Estimation for Multi-agent Reinforcement Learning [Code]

Xu Wan, Chao Yang, Cheng Yang, Jie Song, Mingyang Sun

  • SrSv aims to capture agent interdependence and provide a scalable solution for cooperative MARL.

Full Publications

* denotes co-first authors; # and † denote corresponding authors.

2026

2025

2024

2023

2022 and Prior

Honors and Awards

  • 2026.06: Sun Youxian Academician Scholarship (孙优贤院士奖学金), awarded to only 5 Ph.D. students university-wide, with a RMB 30,000 scholarship
  • 2025.07: Named a Hunyuan Scholar (混元学者), with RMB 100,000 in project funding
  • 2023.10: China Optics Valley Scholarship (中国光谷奖学金), with a RMB 10,000 scholarship
  • 2022.11: First Prize in the 4th China Graduate Student Artificial Intelligence Innovation Competition (Huawei Cup), Top 6 Nationally, with a RMB 30,000 cash award
  • 2022.10: Second Prize in Baidu PaddlePaddle China University Computer Competition, Top 8 Nationally, with a RMB 10,000 cash award
  • 2022.10: National Scholarship for Graduate Students(研究生国家奖学金)
  • 2022.08: First Prize in the 3rd National College Student Mathematical Modeling Competition (Huashu Cup), Top 5% Nationally
  • 2020.04: First Prize in American Mathematical Contest in Modeling (MCM), Top 7.4% Globally
  • 2019.10: National Scholarship for Undergraduate Students(本科生国家奖学金)

Services

Reviewer for ICML 2025-2026, ICLR 2026-2027, NeurIPS 2024-2025, AAAI 2024-2026, TPWRS (Transactions on Power System)

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