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Omar Chehab

Omar Chehab

Assistant Professor

Omar Chehab is joining UW–Madison as a RISE-AI Assistant Professor in the Department of Electrical and Computer Engineering. He completed his graduate training in France, earning a PhD in Mathematical Computer Science at Inria under the supervision of Aapo Hyvärinen and Alexandre Gramfort. He subsequently held postdoctoral positions in the Department of Statistics at ENSAE/CREST, working with Anna Korba, and in the Machine Learning Department at Carnegie Mellon University, working with Pradeep Ravikumar.

His research focuses on principled methods for efficient inference from complex probability distributions. This includes estimating likelihoods from data, generating samples from unnormalized densities, as well as learning representations and discovering causal structure from brain imaging data. His work draws on a range of modern methods, including diffusion models, annealed MCMC, score matching, multi-view independent component analysis, and noise-contrastive estimation. More broadly, he studies these algorithms through the lens of computational and statistical efficiency, aiming to understand their fundamental limits and guide their design.

He regularly publishes at leading machine learning conferences such as NeurIPS, ICML, and ICLR.

  • PhD 2023, Inria, Universite Paris-Saclay
  • MS 2019, ENS Paris
  • MS 2019, ENS Paris-Saclay
  • BS 2015, Lycee Louis-le-Grand
  • BS 2013, Ecole Jeannine Manuel

  • Diffusion and flow models
  • Sampling from unnormalized densities
  • Energy-based models
  • Causal Discovery
  • Density ratio estimation
  • Self-supervised learning
  • Representation learning
  • Brain imaging

  • Heurtebise, A., Chehab, O., Ablin, P., Gramfort, A., & A. Hyvarinen, (2026). Multi-View Causal Discovery without Non-Gaussianity: Identifiability and Algorithms. In International Conference on Machine Learning (ICML).
  • Yu, H., Gutmann, M., Klami, A., & Chehab, O. (2025). Conditional Noise-Contrastive Estimation of Energy-Based Models by Jumping Between Modes. In Workshop on Principles of Generative Modelling, EurIPS.
  • Yu, H., Klami, A., Hyvarinen, A., Korba, A., & Chehab, O. (2025). Density Ratio Estimation with Conditional Probability Paths. In International Conference on Machine Learning (ICML).
  • Chehab, O., Korba, A., Stromme, A., & Vacher, A. (2025). Provable Convergence and Limitations of Geometric Tempering for Langevin Dynamics. In International Conference on Learning Representations (ICLR).
  • Vacher, A., Chehab, O., & Korba, A. (2025). Sampling from multi-modal distributions with polynomial query complexity in fixed dimension via reverse diffusion. In Advances in Neural Information Processing Systems (NeurIPS). Curran Associates, Inc.
  • Heurtebise, A., Chehab, O., Ablin, P., & Gramfort, A. (2025). MVICAD2: Multi-View Independent Component Analysis with Delays and Dilations. IEEE Transactions on Biomedical Engineering.
  • Chehab, O., & Korba, A. (2024). A Practical Diffusion Path for Sampling. In SPIGM Workshop, International Conference on Machine Learning (ICML).
  • Chehab, O., Hyvarinen, A., & Risteski, A. (2024). Provable benefits of annealing for estimating normalizing constants: Importance Sampling, Noise-Contrastive Estimation, and beyond. Spotlight, Advances in Neural Information Processing Systems (NeurIPS), 36.
  • Chehab, O., Gramfort, A., & Hyvarinen, A. (2023). Optimizing the Noise in Self-Supervised Learning: from Importance Sampling to Noise-Contrastive Estimation. ArXiv.
  • Chehab, O., Defossez, A., Loiseau, J., Gramfort, A., & King, J. (2022). Deep Recurrent Encoder: an end-to-end network to model magnetoencephalography at scale. Neurons, Behavior, Data analysis, and Theory, 1, 1-24.