Intro
Hi! — My name is Zixuan Zhang. I am a researcher at OpenAI. I work on ChatGPT post-training.
I received my Ph.D. in Computer Science from UIUC, advised by Prof. Heng Ji. I am honored to have my Ph.D. thesis Completing the knowledge lifecycle for language models advised by Prof. Chengxiang Zhai, Prof. Hanghang Tong, Dr. Kevin Small, and Dr. Scott Wen-tau Yih. Before that, I received my B.S. in Computer Science from Shanghai Jiao Tong University (SJTU), where I did deep reinforcement learning research with Prof. Junchi Yan.
Here is my CV (last updated Apr 02 2026).
What I've worked on:
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Synthetic Data Generation
- Synthesize hard and challenging problems and agentic coding tasks
- Data filtering, curation, rejection sampling, and evaluation pipelines to ensure data quality
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RL Recipe Development
- RL algorithms and training configurations
- Dynamic sampling, multi-source data mixing, curriculum learning, and difficulty/quality controls
- Training/inference collaborations, unbiased data middlewares, and on-policy staleness controls
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Environment Design and Scaling
- Designing verifiable and non-verifiable graders for more reliable reward
- Implementing and scaling sandboxed and containerized environments for agentic tasks
Contact
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