I am a 4th-year PhD candidate in School of Intelligence Science and Technology at Peking University, working with Prof. Y. Zhang. I obtained my bachelor’s degree from the School of Computer Science and Engineering, UESTC in June 2021, under the supervision of Prof. K. Zheng. I’ve also spent time at Tongyi Lab, Baidu Reserch, MSRA, DAMO Academy and Huawei.
My research interests include Agent, RAG and LLM. If you are also interested, please feel free to drop me an email.
I am expected to complete my Ph.D. in June 2026 and will be actively seeking opportunities in both industry and academia. If you are interested, please feel free to reach out.
🔥 News
- 2025.06: 🎉🎉 My paper ZeroSearch, which explores reinforcement learning for search agent, has surpassed 1,000 stars!
- 2025.06: 🎉🎉 Honored to receive the Presidential Scholarship (the highest honor for PhD students at PKU)!
- 2025.05: 🎉🎉 Three papers on multimodal retrieval and RAG were accepted by ACL 2025!
- 2025.04: 🎉🎉 Honored to receive the Academic Star Award (Top-5 students in School of Intelligence Science and Technology)!
- 2024.09: 🎉🎉 One papers on efficient LLM tuning were accepted by NeurIPS 2024!
- 2024.09: 🎉🎉 Three papers on RAG and Agent were accepted by EMNLP 2024!
- 2023.10: 🎉🎉 One paper on dense retrieval was accepted by WSDM 2024!
- 2023.10: 🎉🎉 One paper on multi-hop QA was accepted by EMNLP 2023!
- 2023.08: 🎉🎉 Honored to receive Stars of Tomorrow Award during an internship at Microsoft!
- 2023.05: 🎉🎉 One paper on multi-turn conversation was accepted by ACL 2023!
🌟 Highlight

ZeroSearch: Incentivize the Search Capability of LLMs without Searching
Hao Sun, Z. Qiao, J. Guo, X. Fan, Y. Hou, Y. Jiang, P. Xie, F. Huang, J. Zhou
Homepage | Paper | Code | Model 🏆 1000+ stars
机器之心 | 量子位 | 通义大模型 | Twitter | Huggingface | VentureBeat
A novel reinforcement learning framework that incentivizes the search capability of LLMs with simulated searches during training.
📝 Publications

Unveil: Unified Visual-Textual Integration and Distillation for Multi-modal Document Retrieval
Hao Sun, Y. Hou, J. Guo, B. Wang, C. Yang, J. Ni, Y. Zhang
The Annual Meeting of the Association for Computational Linguistics (ACL), 2025
We propose a novel visual-textual embedding framework that effectively integrates textual and visual features.

Enhancing Retrieval-Augmented Generation via Evidence Tree Search
Hao Sun, H. Cai, Y. Li, X. Fan, X. Wei, S. Wang, Y. Zhang, D. Yin
The Annual Meeting of the Association for Computational Linguistics (ACL), 2025
We propose a novel framework that reformulates evidence retrieval as a dynamic tree expansion process.

Towards Verifiable Text Generation with Evolving Memory and Self-Reflection
Hao Sun, H. Cai, B. Wang, Y. Hou, X. Wei, S. Wang, Y. Zhang, D. Yin
The Conference on Empirical Methods in Natural Language Processing (EMNLP), 2024
Improving citation generation with a two-tier verifier and active retrieval mechanism.

Retrieved In-Context Principles from Previous Mistakes
Hao Sun, Y. Jiang, B. Wang, Y. Hou, Y. Zhang, P. Xie, F. Huang
The Conference on Empirical Methods in Natural Language Processing (EMNLP), 2024
Enabling LLMs to learn from mistakes by proving question-level and task-level principles.

Hao Sun, J. Wu, H. Cai, X. Wei, Y. Feng, B. Wang, S. Wang, Y. Zhang, D. Yin
The Conference on Empirical Methods in Natural Language Processing (EMNLP), 2024
Enabling adaptive switching between local agent and cloud agent through collaborative learning.

LEAD: Liberal Feature-based Distillation for Dense Retrieval
Hao Sun, X. Liu, Y. Gong, A. Dong, J. Lu, Y. Zhang, L. Yang, R. Majumder, N. Duan
The ACM International Conference on Web Search and Data Mining (WSDM), 2024, Oral
Distill the intermediate features from teacher to student without the constraints on model architecture or tokenizers.

Allies: Prompting Large Language Model with Beam Search
Hao Sun, X. Liu, Y. Gong, Y. Zhang, N. Duan
The Conference on Empirical Methods in Natural Language Processing (EMNLP), 2023, Findings
Improving the knowledge scope and robustness of LLMs with Beam Search.

History Semantic Graph Enhanced Conversational KBQA with Temporal Information Modeling
Hao Sun, Y.g Li, L. Deng, B. Li, B. Hui, B. Li, Y. Lan, Y. Zhang, Y. Li
The Annual Meeting of the Association for Computational Linguistics (ACL), 2023
Modeling history conversation information with History Semantic Graph.

Hao Sun, Y. Li, Y. Zhang
The SIAM International Conference on Data Mining (SDM), 2022
Capturing complex transition patterns between concepts through Graph Neural Network.

PeriodicMove: Shift-aware Human Mobility Recovery with Graph Neural Network
Hao Sun, C. Y.g, L. Deng, F. Zhou, F. Huang, K. Zheng
The ACM International Conference on Information and Knowledge Management (CIKM), 2021
Capturing multi-level periodicity and shifting periodicity of human mobility using attention mechanism.

Personalized Dynamic Knowledge-Aware Recommendation with Hybrid Explanations
Hao Sun, Z. Wu, Y. Cui, L. Deng, Y. Zhao, K. Zheng
The International Conference on Database Systems for Advanced Applications (DASFAA), 2021
Providing personalized and hybrid explanations for the recommendations.

Cross-model Control: Improving Multiple Large Language Models in One-time Training
J. Wu, Hao Sun, H. Cai, L. Su, S. Wang, D. Yin, X. Li, M. Gao
The Annual Conference on Neural Information Processing Systems (NeurIPS), 2024
Improves multiple LLMs in one-time training with a portable tiny language model.

A Neural Corpus Indexer for Document Retrieval
Y. Wang, Y. Hou, H. Wang, Z. Miao, S. Wu, Hao Sun, Q. Chen, Y. Xia, C. Chi, G. Zhao, Z. Liu, X. Xie, H. Allen Sun, W. Deng, Q. Zhang, M. Yang
The Annual Conference on Neural Information Processing Systems (NeurIPS), 2022
Paper | Code 🏆 Outstanding Paper Award
Propose an end-to-end differentiable document retrieval model that can significantly outperform both inverted index and dense retrieval solutions.

Unraveling the Mechanics of Learning-Based Demonstration Selection for In-Context Learning
H Liu, W. Wang, Hao Sun, C. Tian, C. Kong, X. Dong, H. Li
The Annual Meeting of the Association for Computational Linguistics (ACL), 2025
Investigate the working mechanism of In-Context Learning.

PA-RAG: RAG Alignment via Multi-Perspective Preference Optimization
J Wu, H Cai, L Yan, Hao Sun, X Li, S Wang, D Yin, M Gao
The 2025 Annual Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics (NAACL), 2025
Optimize the RAG generator to align with RAG requirements comprehensively.

Sequential-Knowledge-Aware Next POI Recommendation: A Meta-Learning Approach
Y. Cui, Hao Sun, Y. Zhao, H. Yin, K. Zheng
The ACM Transactions on Information Systems (TOIS), 2021
Utilize sequential, spatiotemporal, and social knowledge to recommend the next POI for a location-based social network user.

Robust Domain Misinformation Detection via Multi-modal Feature Alignment
H Liu, W Wang, Hao Sun, A Rocha, H Li
IEEE Transactions on Information Forensics and Security (TIFS), 2023
Reduces the domain shift by aligning the joint distribution of textual and visual modalities through an inter-domain alignment module.

S2TUL: A Semi-Supervised Framework for Trajectory-User Linking
L. Deng, Hao Sun, Y. Zhao, S. Liu, K. Zheng
The ACM International Conference on Web Search and Data Mining (WSDM), 2023
Capture fine-grained intra-trajectory information by passing the trajectories into the sequential neural networks.

Efficient Trajectory Similarity Computation with Contrastive Learning
L. Deng, Y. Zhao, Z. Fu, Hao Sun, S. Liu, K. Zheng
The ACM International Conference on Information and Knowledge Management (CIKM), 2022
Employ a contrastive learning mechanism to learn the representations of trajectories, which are then used to calculate the dissimilarity between them.

Efficient and Effective Similar Subtrajectory Search: A Spatial-aware Comprehension Approach
L. Deng, Hao Sun, R. Sun, Y. Zhao, H. Su
The ACM Transactions on Intelligent Systems and Technology (TIST), 2022
Propose a Similar Subtrajectory Search with a Graph Neural Networks framework.

Fusing Local and Global Mobility Patterns for Trajectory Recovery
L. Deng, Y. Zhao, Hao Sun, C. Yang, J. Xie, K. Zheng
The ACM International Conference on Information and Knowledge Management (CIKM), 2022
Propose a neural attention model based on graph convolutional networks to enhance the accuracy of trajectory recovery.

Boosting Disfluency Detection with Large Language Model as Disfluency Generator
Z. Cheng, J. Guo, Hao Sun, Y. Zhang
The IEEE International Conference on Multimedia & Expo (ICME), 2024
Propose a framework that addresses data sparsity issues by generating disfluent data using LLM as augmentation data.
📒 Preprint

SimCNS: Simple Curriculum Negative Sampling for Multi-Source Dense Retrieval
Hao Sun, X. Liu, Y. Gong, A. Dong, G. Shi, Y. Zhang, L. Yang, N. Duan
Under Review
Select the most important negative samples for multi-source dense retrieval
🎖 Honors and Awards
- 2025.06 Presidential Scholarship, Peking University.
- 2025.04 Academic Star Award, Peking University.
- 2024.06 First Prize of Challenge Cup Competition, Peking University.
- 2023.09 Merit Student, Peking University.
- 2023.09 Schlumberger Scholarship, Peking University.
- 2023.08 Stars of Tomorrow Award, Microsoft.
- 2023.06 First Prize of Challenge Cup Competition, Peking University.
- 2022.12 Outstanding Paper Award, NeurIPS 2022.
- 2021.06 Outstanding Graduation Thesis for Undergraduates, UESTC.
- 2021.06 Outstanding Graduate, UESTC.
- 2019.12 National Scholarship.
- 2018.09 National Scholarship.
📖 Educations
- 2021.09 - Present, Ph.D. Candidate, Peking University.
- 2017.09 - 2021.06, Undergraduate, University of Electronic Science and Technology of China.
📚 Services
- Program Committee / Reviewer: NeurIPS 2024-25, ICLR 2024-25, ICML 2024-25, ACL 2022-25, EMNLP 2022-25
- Secondary Reviewer: AAAI 2022, CIKM 2021-22, ICDM 2021-23, COLING 2022-23, DASFAA 2022-23
👩🏻🏫 Teaching
- Teaching Assistant, Computer Networks and Web Technologies, Peking University, Fall 2023
💻 Internships
- Tongyi Lab, focusing on Agent and RAG.
- Baidu Research, focusing on RAG and LLM.
- Microsoft Research Asia (MSRA), focusing on dense retrieval.
- DAMO Academy, focusing on multi-turn conversation.
- HUAWEI Research, focusing on spatial-temporal data analysis.