About me

I am a postdoctoral researcher at EPFL, working with Prof. Antoine Bosselut. I received my Ph.D. from The Chinese University of Hong Kong, advised by Prof. Kam-Fai Wong, and was a visiting researcher at LMU Munich with Prof. Hinrich Schütze. Earlier, I received my M.S. from Peking University and B.S. from Northwestern Polytechnical University.

My research goal is to make language models more capable without making them less reliable. In post-training the supervision is always imperfect, yet standard recipes are designed as if it were clean. I work on understanding how that imperfection surfaces in the trained model, and on building training methods that keep models capable and reliable in spite of it.

• Learning from a sparse RL signal. In practice, RL for LLMs gives sparse rewards at the end of a long trajectory. Through denser credit assignment and wider exploration, we make it a stronger learning signal. [BRIDGE ICML’26, EEPO ICLR’26]
• Making alignment survive what comes after it. LLM alignment is fragile: a range of downstream operations can undo it, from adversarial inputs to malicious finetuning. We build robust alignment methods that hold up under such perturbations. [PEARL ICLR’25, VAA ICML’25]
• Trusting text the model produced. Post-training now runs largely on the model’s own output. We asked whether that output can be trusted — evaluating LLMs as knowledge generators, and making what they write attributable. [WatME ACL’24, CONNER EMNLP’23]

Feel free to reach out if you’d like to chat about research or explore potential opportunities.

News

• [05/2026] One paper accepted at EMNLP 2026.
• [06/2026] Passed my Ph.D. oral defense.
• [05/2026] One paper on densifying RL rewards accepted at ICML 2026.
• [01/2026] One paper on enhancing RL exploration accepted at ICLR 2026.
• [05/2025] One paper on resilient safety alignment accepted at ICML 2025.
• [02/2025] One paper on robust instruction tuning accepted at ICLR 2025.
• [05/2024] One paper on LLM watermarking accepted at ACL 2024.
• [10/2023] One paper on LLM knowledge evaluation accepted at EMNLP 2023.

Selected publications (Full list)

• Beyond Two-Stage Training: Cooperative SFT and RL for LLM Reasoning
  Liang Chen, Xueting Han, Li Shen, Jing Bai, Kam-Fai Wong
  ICML 2026

• EEPO: Exploration-Enhanced Policy Optimization via Sample-Then-Forget
  Liang Chen, Xueting Han, Qizhou Wang, Bo Han, Jing Bai, Hinrich Schütze, Kam-Fai Wong
  ICLR 2026

• Vulnerability-Aware Alignment: Mitigating Uneven Forgetting in Harmful Fine-Tuning
  Liang Chen, Xueting Han, Li Shen, Jing Bai, Kam-Fai Wong
  ICML 2025

• PEARL: Towards Permutation-Resilient LLMs
  Liang Chen, Li Shen, Yang Deng, Xiaoyan Zhao, Bin Liang, Kam-Fai Wong
  ICLR 2025

• WatME: Towards Lossless Watermarking Through Lexical Redundancy
  Liang Chen, Yatao Bian, Yang Deng, Deng Cai, Shuaiyi Li, Peilin Zhao, Kam-Fai Wong
  ACL 2024

• Beyond Factuality: A Comprehensive Evaluation of Large Language Models as Knowledge Generators
  Liang Chen, Yang Deng, Yatao Bian, Zeyu Qin, Bingzhe Wu, Tat-Seng Chua, Kam-Fai Wong
  EMNLP 2023

Talks

• Learning Good LLMs from Imperfect Data
  Invited Talk, Microsoft Research Asia – November 2025
  Host: Dr. Jing Bai

• Learning Good LLMs from Imperfect Data
  Invited Talk, EPFL – October 2025
  Host: Prof. Antoine Bosselut

• Beyond Two-Stage Training: Cooperative SFT and RL for Improved LLM Reasoning
  PhD Seminar, LMU Munich – August 2025
  Host: Prof. Hinrich Schütze

• Vulnerability-Aware Alignment: Protect Open-Source LLMs against Unsafe Fine-tuning
  AI Time, Online Live – June 2025

• Towards Trustworthy LLMs: Improving Robustness via Post-Training Optimization
  PhD Seminar, LMU Munich – May 2025
  Host: Prof. Hinrich Schütze

Teaching

Teaching assistant at CUHK:

• Operations Research II (SEEM3440)
• Engineering Innovation and Entrepreneurship (SEEM3450)
• Information Technology Management (SEEM5730)

Internships

• Microsoft Research, Systems Research Group
• Tencent AI Lab, Machine Learning Center

Community service

• Program Committee for AAAI 2027.

• Reviewer for ICML, ICLR, NeurIPS, TMLR, AISTATS, ACL, EMNLP, and NAACL.

Miscellaneous

Outside of research, I enjoy walking in parks, as well as swimming, hiking, and table tennis.

During my undergrad, I was the runner-up in the Freshmen Cup table tennis singles match and won the team championship three times.

Live long enough to live forever