Rob Brekelmans
Rob Brekelmans is a machine-learning researcher who works on probabilistic inference for generative models, from language models to diffusion models. After early papers on total correlation explanation in 2018 and annealed importance sampling in 2020, he earned a PhD at the University of Southern California in 2022, having worked with Greg Ver Steeg and Aram Galstyan. He coauthored Action Matching with Kirill Neklyudov, Daniel Severo and Alireza Makhzani in 2023, and won an ICML 2024 Best Paper award with Stephen Zhao, Alireza Makhzani and Roger Grosse for twisted Sequential Monte Carlo in language models. A 2025 paper on Feynman-Kac Correctors brought Sequential Monte Carlo resampling to pretrained diffusion models. He is a postdoctoral fellow at the Vector Institute in Toronto, working with Alireza Makhzani and Roger Grosse.
- Now at
- Vector Institute
Timeline
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2018
Auto-encoding total correlation explanation
In 2018, he coauthors "Auto-Encoding Total Correlation Explanation" with Shuyang Gao, Greg Ver Steeg and Aram Galstyan. The paper introduces a variational lower bound to total correlation explanation (CorEx) and finds that it is equivalent to the variational autoencoder bound under certain conditions.
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2020
Annealed importance sampling with q-paths
In 2020, he and six coauthors, including Vaden Masrani, Frank Wood and Frank Nielsen, explore annealed importance sampling with q-paths, a family that includes the geometric path as a special case. The paper carries a Best Paper Award at the NeurIPS Workshop on Deep Learning through Information Geometry.
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2022
PhD at USC and DeepMind
He graduates with a PhD from the University of Southern California in 2022, having worked with Greg Ver Steeg and Aram Galstyan, and interns with the AI Safety Analysis team at DeepMind alongside Pedro Ortega and Tim Genewein. In 2022, he coauthors "Your Policy Regularizer is Secretly an Adversary" with Genewein, Ortega, Shane Legg and others, showing that the robustness of policy regularization comes from hedging against worst-case reward perturbations.
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2023
Action Matching at ICML
He coauthors Action Matching with Kirill Neklyudov, Daniel Severo and Alireza Makhzani, presented at the 40th International Conference on Machine Learning in 2023. The method learns the dynamics of a system from independent samples of its time evolution, with a training objective that avoids back-propagation through differential equations or optimal transport solvers.
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2024
ICML 2024 Best Paper
At ICML 2024, "Probabilistic Inference in Language Models via Twisted Sequential Monte Carlo", by Stephen Zhao, Rob Brekelmans, Alireza Makhzani and Roger Grosse, receives a Best Paper award. The method uses learned twist functions to estimate the expected future value of the potential at each timestep, which focuses inference-time computation on promising partial sequences.
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2025
Feynman-Kac Correctors for diffusion
The 42nd International Conference on Machine Learning in 2025 publishes "Feynman-Kac Correctors in Diffusion: Annealing, Guidance, and Product of Experts", which he coauthors with Marta Skreta, Alexander Tong, Kirill Neklyudov, Arnaud Doucet and others. The method derives a weighted simulation scheme for sampling from annealed, geometric-averaged or product distributions of pretrained score-based models, using Sequential Monte Carlo resampling.
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As of October 2026
Postdoc at the Vector Institute
He works as a postdoctoral fellow at the Vector Institute in Toronto, with Alireza Makhzani and Roger Grosse.
Career
- NowVector InstitutePostdoctoral Fellow
- 2022Google DeepMindIntern
Education
Sources and credits
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- [1802.05822] Auto-Encoding Total Correlation Explanation
- [2012.07823] Annealed Importance Sampling with q-Paths
- Rob Brekelmans
- [2203.12592] Your Policy Regularizer is Secretly an Adversary
- Action Matching: Learning Stochastic Dynamics from Samples
- ICML 2024 Awards
- [2404.17546] Probabilistic Inference in Language Models via Twisted Sequential Monte Carlo
- Feynman-Kac Correctors in Diffusion: Annealing, Guidance, and Product of Experts


