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arXiv · 2603.18992

Foundations of Schr\"odinger Bridges for Generative Modeling

Sophia Tang
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Abstract

At the core of modern generative modeling frameworks, including diffusion models, score-based models, and flow matching, is the task of transforming a simple prior distribution into a complex target distribution through stochastic paths in probability space. Schr\"odinger bridges provide a unifying principle underlying these approaches, framing the problem as determining an optimal stochastic bridge between marginal distribution constraints with minimal-entropy deviations from a pre-defined reference process. This guide develops the mathematical foundations of the Schr\"odinger bridge problem, drawing on optimal transport, stochastic control, and path-space optimization, and focuses on its dynamic formulation with direct connections to modern generative modeling. We build a comprehensive toolkit for constructing Schr\"odinger bridges from first principles, and show how these constructions give rise to generalized and task-specific computational methods.

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Sophia Tang. 2026-03-19. Foundations of Schr\"odinger Bridges for Generative Modeling. https://arxiv.org/abs/2603.18992

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