Suriya Gunasekar
Suriya Gunasekar is a machine learning researcher and one of the authors behind Microsoft's Phi family of small language models. They received a PhD from the University of Texas at Austin in 2016, studied the implicit bias of gradient descent in papers from 2017 and 2018, and were a research assistant professor at the Toyota Technological Institute at Chicago before joining Microsoft Research. In 2023, Gunasekar headed the author list of Textbooks Are All You Need, which introduced the 1.3B-parameter code model phi-1, and went on to coauthor the Phi-3 and Phi-4 technical reports in 2024 and the Phi-4-reasoning report in 2025. They are a Principal Research Manager at Microsoft Research and part of the Physics of AGI group that pioneered the Phi models.
- Now at
- Microsoft Research
- Works
- 43
- Citations
- 1,457
- h-index
- 18
- Badges
Publication numbers from OpenAlex, as of 22 October 2026.
Timeline
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2016
PhD at UT Austin
They receive a PhD from the University of Texas at Austin in 2016, advised by Joydeep Ghosh.
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2017–2018
Implicit bias of gradient descent
In 2017, they coauthor Implicit Regularization in Matrix Factorization with Blake Woodworth, Srinadh Bhojanapalli, Behnam Neyshabur and Nathan Srebro, which conjectures that gradient descent on a full-dimensional factorization converges to the minimum nuclear norm solution. A 2018 paper with Jason Lee, Daniel Soudry and Nathan Srebro shows that gradient descent on full-width linear convolutional networks converges to a predictor related to a bridge penalty in the frequency domain.
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2019
Visiting scientist at Simons Institute
In 2019, they join the Foundations of Deep Learning program at the Simons Institute for the Theory of Computing as a visiting scientist. They hold a research assistant professor post at the Toyota Technological Institute at Chicago before moving to Microsoft Research.
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2023
Textbooks Are All You Need
In 2023, they head the author list of Textbooks Are All You Need, which introduces phi-1, a Transformer-based language model for code with 1.3B parameters, trained for 4 days on 8 A100s.
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December 2023
The Phi-2 small language model
Microsoft Research publishes its Phi-2 announcement in December 2023, with them among the named contributors. On complex benchmarks, Phi-2 matches or outperforms models up to 25x larger.
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2024
Phi-3 and Phi-4 reports
They coauthor the Phi-3 Technical Report in 2024, which introduces phi-3-mini, a 3.8 billion parameter language model trained on 3.3 trillion tokens. The Phi-4 Technical Report of December 2024, also with them as an author, presents phi-4, a 14-billion parameter model built with a training recipe centered on data quality.
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April 2025
The Phi-4-reasoning model
The Phi-4-reasoning Technical Report appears in April 2025 with them among its authors. It introduces Phi-4-reasoning, a 14-billion parameter reasoning model trained by supervised fine-tuning of Phi-4.
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As of October 2026
Principal Research Manager at Microsoft
They are a Principal Research Manager at Microsoft Research and part of the Physics of AGI group that pioneered the Phi family of language models. Their work focuses on improving language model capabilities through scale and data curation.
Career
- NowMicrosoft ResearchPrincipal Research Manager
- 2019Simons Institute for the Theory of ComputingVisiting Scientist
- 2019–2024Microsoft
- 2018–2020Toyota Technological Institute at ChicagoResearch Assistant Professor
Education
Sources and credits
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- Suriya Gunasekar
- Implicit Regularization in Matrix Factorization
- Implicit Bias of Gradient Descent on Linear Convolutional Networks
- Suriya Gunasekar
- Textbooks Are All You Need
- Phi-2: The surprising power of small language models
- Phi-3 Technical Report: A Highly Capable Language Model Locally on Your Phone
- Phi-4 Technical Report
- Phi-4-reasoning Technical Report


