Sebastian Ament

About

Portrait of Sebastian Ament

I am a Staff Research Scientist in the Adaptive Experimentation group at Meta, where I develop sample-efficient optimization methods with a focus on efficient AutoML for large machine learning models. Before joining Meta, I completed my PhD in computer science at Cornell University, working with Professor Carla Gomes. My research interests include Bayesian optimization, sparse optimization, and active learning, with applications in materials science and beyond. My work at Meta has also involved leveraging Bayesian optimization to optimize the sustainability of the concrete mixes used in Meta's data centers, reducing the environmental impact while increasing strength and stability.

When I am not penciling Greek letters or hunting down missing minus signs in code, I enjoy cycling, dancing tango, and playing the piano. Hear me play a tango that I transcribed here

Selected Projects

Sustainable Concrete via Bayesian Optimization

Eight percent of global CO₂ emissions come from cement production — the dominant source of emissions in data center construction. In collaboration with Amrize and the University of Illinois Urbana-Champaign, we used Bayesian optimization to discover lower-carbon concrete formulations that are 13% stronger, 43% faster-setting, and 19% lower in CO₂ — at no extra cost and using only standard materials. The optimized mix has been deployed at Meta's data center in Rosemount, MN.

Sustainable Concrete via Bayesian Optimization

LogEI: Unexpected Improvements to Expected Improvement

Expected Improvement (EI) is the most widely used acquisition function in Bayesian optimization, yet it suffers from numerical pathologies — vanishing gradients and poor acquisition optimization. LogEI reformulates the EI family with principled transformations that enable reliable gradient-based optimization. The result is substantially improved sample efficiency across a wide range of tasks, even outperforming state-of-the-art entropy search acquisition functions. LogEI generalizes to the noisy, multi-objective, and constrained settings and is the default in BoTorch and Meta's Ax platform, powering large-scale adaptive experimentation at Meta and beyond.

Scientific Autonomous Reasoning Agent (SARA)

SARA is an autonomous experimentation system that integrates robotic materials synthesis with a hierarchy of AI methods to accelerate scientific discovery. By combining lateral gradient laser spike annealing with nested active learning cycles and end-to-end uncertainty quantification, SARA autonomously maps synthesis phase diagrams — achieving orders-of-magnitude acceleration in exploring metastable materials. We demonstrated SARA's capabilities by mapping the Bi₂O₃ system, including conditions for stabilizing δ-Bi₂O₃ at room temperature, a critical development for electrochemical technologies.

Publications

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