Jan Ludziejewski
Jan Ludziejewski is a machine-learning researcher whose work spans computer-vision tracking, mixture-of-experts language models and reasoning systems. He worked at QED Software and IDEAS NCBR while pursuing doctoral research at the University of Warsaw. In 2024, he coauthored ICML and NeurIPS studies of MoE scaling and continuous token routing. His 2025 work includes a study of memory-efficient MoE models and Magistral, Mistral AI's first reasoning model. He earned a University of Warsaw doctorate in 2026 and is an AI Research Scientist at Mistral AI, where he coauthored 2026 papers on Ministral 3 and Voxtral TTS.
- Now at
- Mistral AI
Timeline
-
2017–2025
From QED Software to IDEAS
He joins QED Software as a machine-learning specialist in 2017 and moves to IDEAS NCBR as a doctoral researcher in 2022. In 2023, he is a doctoral student at the University of Warsaw's Institute of Computer Science and an IDEAS NCBR researcher, with interests in neural-network music generation.
-
2020
Arahub human tracking
In 2020, he coauthors a paper introducing Arahub, a system that combines computer-vision tracking with smartphone signals for interactive applications.
-
2024
Fine-grained MoE scaling
In 2024, he coauthors an ICML study that introduces granularity as a way to control expert size and derive mixture-of-experts scaling laws under a compute budget.
-
2024
Mixture of Tokens
In 2024, he coauthors Mixture of Tokens, a continuous architecture that assigns tokens from different examples to each expert and scales toward sparse MoE parameter counts.
-
February 2025
Memory-efficient MoE scaling
In 2025, he coauthors Joint MoE Scaling Laws, which shows that MoE models can be more memory-efficient than dense models under fixed compute and memory budgets.
-
June 2025
Magistral reasoning
In June 2025, he coauthors Magistral, Mistral AI's first reasoning model.
-
June 2026
A University of Warsaw doctorate
In June 2026, he earns a computer-science doctorate at the University of Warsaw under supervisor Marek Cygan, with a dissertation on improving mixture-of-experts language models.
-
Since March 2025
Research scientist at Mistral
Since March 2025, he is an AI Research Scientist in Mistral AI's Research department. In 2026, he coauthors Ministral 3, a family of parameter-efficient language models, and Voxtral TTS, an expressive multilingual text-to-speech model.
Career
- Since 2025Mistral AIAI Research Scientist
- 2022–2025IDEAS NCBRDoctoral researcher
- 2017–2022QED SoftwareMachine-learning specialist
Education
- From 2023University of WarsawPhD
Sources and credits
Photo: We have no published photo of Jan Ludziejewski yet. Send us a free-licensed photo.
- 10 Mistral AI research scientists
- W rytmie AI. Jak wykorzystać sztuczną inteligencję w tworzeniu muzyki? Nowy odcinek podcastu
- Integrated Human Tracking Based on Video and Smartphone Signal Processing within the Arahub System
- Scaling Laws for Fine-Grained Mixture of Experts
- Mixture of Tokens: Continuous MoE through Cross-Example Aggregation
- Joint MoE Scaling Laws: Mixture of Experts Can Be Memory Efficient
- Magistral
- Jan Ludziejewski
- Ministral 3
- Voxtral TTS

