Xuxi Chen
Xuxi Chen is a machine-learning researcher whose work spans positive-unlabeled learning, sparse networks, multilingual translation and language models. He studied statistics at USTC while working with VITA in 2019, then coauthored research on self-training and efficient sparse networks. His later work ranges from Orca 2's reasoning methods for small language models to Lingual-SMoE's multilingual routing and a study of alignment behavior. After completing his VITA PhD in Summer 2025, he is a quantitative researcher at XTX Markets as of October 2026.
- Now at
- XTX Markets
- Badges
Timeline
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2019
Statistics at USTC
During Summer 2019, he works with VITA as an undergraduate in statistics at USTC and plans to join the group for a PhD.
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2020
Self-PU training
In 2020, he coauthors Self-PU, a positive-unlabeled learning framework that combines self-training with self-paced training to identify confident positive and negative examples.
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2021
Efficient lottery-ticket finding
In 2021, he coauthors Efficient Lottery Ticket Finding: Less Data is More, which uses a Pruning-Aware Critical set of training data to find winning subnetworks with fewer training iterations. In Fall 2021, he begins PhD study with VITA.
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2022
Sparse tickets in low-data settings
In 2022, he coauthors Sparse Winning Tickets are Data-Efficient Image Recognizers. In experiments with 50 to 100 examples per class, the paper finds that sparse winning tickets outperform the original dense networks.
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2022
Structurally sparse lottery tickets
Also in 2022, he coauthors Coarsening the Granularity: Towards Structurally Sparse Lottery Tickets. The method refills important channels and regroups nonzero elements to create channel- and group-wise sparse networks with inference speedups.
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2023
Orca 2 reasoning research
In 2023, he coauthors Microsoft's Orca 2, which teaches small language models to choose different solution strategies for different tasks. Microsoft releases Orca 2 as open source to support further research.
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2024
Lingual-SMoE for translation
In 2024, he coauthors Lingual-SMoE for multilingual machine translation. It uses language representations to group experts and adapts the number of active experts for each target language to its translation difficulty.
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As of October 2026
Quantitative researcher at XTX Markets
In 2025, he coauthors Extracting and Understanding the Superficial Knowledge in Alignment, a study of how alignment fine-tuning changes shallow token selection in language models. He completes his VITA PhD in Summer 2025. As of October 2026, he is a quantitative researcher at XTX Markets.
Career
- NowXTX MarketsQuantitative researcher
- 2019VITAUndergraduate
Education
- 2025VITAPhD
- From 2019University of Science and Technology of ChinaUndergraduate
Sources and credits
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- Team | VITA Group
- Self-PU: Self Boosted and Calibrated Positive-Unlabeled Training
- Efficient Lottery Ticket Finding: Less Data is More
- Sparse Winning Tickets are Data-Efficient Image Recognizers
- Coarsening the Granularity: Towards Structurally Sparse Lottery Tickets
- Orca-2: Teaching Small Language Models How to Reason
- Sparse MoE with Language Guided Routing for Multilingual Machine Translation
- Extracting and Understanding the Superficial Knowledge in Alignment

