Stochastic Control for Fine-tuning Diffusion Models: Optimality, Regularity, and Convergence
On the map: Diffusion models → Diffusion and flow policies for robotics
Abstract (arXiv)
Diffusion models have emerged as powerful tools for generative modeling, demonstrating exceptional capability in capturing target data distributions from large datasets. However, fine-tuning these massive models for specific downstream tasks, constraints, and human preferences remains a critical challenge. While recent advances have leveraged reinforcement learning algorithms to tackle this problem, much of the progress has been empirical, with limited theoretical understanding. To bridge this gap, we propose a stochastic control framework for fine-tuning diffusion models. Building on denoising diffusion probabilistic models as the pre-trained reference dynamics, our approach integrates linear dynamics control with Kullback-Leibler regularization. We establish the well-posedness and regularity of the stochastic control problem and develop a policy iteration algorithm (PI-FT) for numerical solution. We show that PI-FT achieves global convergence at a linear rate. Unlike existing work that assumes regularities throughout training, we prove that the control and value sequences generated by the algorithm maintain the regularity. Additionally, we explore extensions of our framework to parametric settings and continuous-time formulations, and demonstrate the practical effectiveness of the proposed PI-FT algorithm through numerical experiments. Our code is available at https://github.com/yinbinhan/fine-tuning-of-diffusion-models.
Key facts. Cited by 19 papers in the map (data through 14 Oct 2026). Placed in Diffusion and flow policies for robotics, one of 14 directions in Diffusion models. Builds on 54 of its 78 references that are in the map. First posted on arXiv 24 Dec 2024.
Builds on
54 of 78 references.
Closest ancestors · 8
Same direction, newest first
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- 2024Reward-Directed Score-Based Diffusion Models via q-Learning7 Sep
- 2024Understanding Reinforcement Learning-Based Fine-Tuning of Diffusion Models: A Tutorial and Review18 Jul
- 2024Adding Conditional Control to Diffusion Models with Reinforcement Learning17 Jun
- 2024Feedback Efficient Online Fine-Tuning of Diffusion Models26 Feb
- 2023Diffusion Model Alignment Using Direct Preference Optimization21 Nov
- 2023Training Diffusion Models with Reinforcement Learning22 May
Other references · 46
- 2020Denoising Diffusion Probabilistic Modelscited by 21,076
- 2021High-Resolution Image Synthesis with Latent Diffusion Modelscited by 18,863
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- 2015Deep Unsupervised Learning using Nonequilibrium Thermodynamicscited by 7,058
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- 2023SDXL: Improving Latent Diffusion Models for High-Resolution Image Synthesiscited by 4,356
- 2019Generative Modeling by Estimating Gradients of the Data Distributioncited by 4,101
- 2022DreamBooth: Fine Tuning Text-to-Image Diffusion Models for Subject-Driven Generationcited by 3,300
- 2018Neural Tangent Kernel: Convergence and Generalization in Neural Networkscited by 2,621
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- 2016Tutorial on Variational Autoencoderscited by 409
- 2023Emu: Enhancing Image Generation Models Using Photogenic Needles in a Haystackcited by 279
- 2018Global Convergence of Policy Gradient Methods for the Linear Quadratic Regulatorcited by 250
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- 2018Derivative-Free Methods for Policy Optimization: Guarantees for Linear Quadratic Systemscited by 67
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- 2020On Linear Convergence of Policy Gradient Methods for Finite MDPscited by 52
- 2020Policy Gradient Methods for the Noisy Linear Quadratic Regulator over a Finite Horizoncited by 50
- 2024Neural Network-Based Score Estimation in Diffusion Models: Optimization and Generalizationcited by 42
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- 2019LQR through the Lens of First Order Methods: Discrete-time Casecited by 40
- 2020Single-Timescale Actor-Critic Provably Finds Globally Optimal Policycited by 34
- 2019Understanding the Limitations of Conditional Generative Modelscited by 28
- 2023Improved Sample Complexity Analysis of Natural Policy Gradient Algorithm with General Parameterization for Infinite Horizon Discounted Reward Markov Decision Processescited by 25
- 2024Bridging Model-Based Optimization and Generative Modeling via Conservative Fine-Tuning of Diffusion Modelscited by 25
- 2021Doubly Robust Off-Policy Actor-Critic: Convergence and Optimalitycited by 21
- 2021Exploration-exploitation trade-off for continuous-time episodic reinforcement learning with linear-convex modelscited by 21
- 2022Single Time-scale Actor-critic Method to Solve the Linear Quadratic Regulator with Convergence Guaranteescited by 14
- 2023A Policy Gradient Framework for Stochastic Optimal Control Problems with Global Convergence Guaranteecited by 10
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- 2023Policy Gradient Converges to the Globally Optimal Policy for Nearly Linear-Quadratic Regulatorscited by 5
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Citing papers per year: 2025: 7; 2026: 12.
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- 2025TR2-D2: Tree Search Guided Trajectory-Aware Fine-Tuning for Discrete Diffusioncited by 14
- 2026Conditional Diffusion Guidance under Hard Constraint: A Stochastic Analysis Approachcited by 11
- 2025Composition and Alignment of Diffusion Models using Constrained Learningcited by 10
- 2025Understanding Sampler Stochasticity in Training Diffusion Models for RLHFcited by 7
- 2026Adjoint Matching through the Lens of the Stochastic Maximum Principle in Optimal Controlcited by 6
- 2026Inference-Time Alignment for Diffusion Models via Variationally Stable Doob's Matchingcited by 5
- 2026Improved techniques for fine-tuning flow models via adjoint matching: a deterministic control pipelinecited by 5
- 2025Continuous Q-Score Matching: Diffusion Guided Reinforcement Learning for Continuous-Time Controlcited by 4
- 2025Is RL fine-tuning harder than regression? A PDE learning approach for diffusion modelscited by 3
- 2025Schr"odinger bridge for generative AI: Soft-constrained formulation and convergence analysiscited by 3
- 2026Supervised Guidance Training for Infinite-Dimensional Diffusion Modelscited by 3
- 2026Diffusion Controller: Framework, Algorithms and Parameterizationcited by 2
7 more
- 2026Inference-Time Attribute Distribution Alignment for Unconditional Diffusioncited by 2
- 2025Coffee: Controllable Diffusion Fine-tuningcited by 1
- 2026FluxLite: Inference-Time Proposal Control for Discrete Diffusion Modelscited by 1
- 2026Continuous-time reinforcement learning: ellipticity enables model-free value function approximationcited by 0
- 2026Sobolev Regularized Score Difference Estimation in Diffusion Modelscited by 0
- 2026Error-Corrected Inference-Time Scaling for Imperfect Diffusion Modelscited by 0
- 2026Weighted Adjoint Matching: Finetuning Flow Matching Models with Time-Dependent Control Costcited by 0
- 2026Weighted Adjoint Matching: Finetuning Flow Matching Models with Time-Dependent Control Cost14 Oct 2026
- 2026Error-Corrected Inference-Time Scaling for Imperfect Diffusion Models1 Oct 2026
- 2026FluxLite: Inference-Time Proposal Control for Discrete Diffusion Models28 Sep 2026
- 2026Sobolev Regularized Score Difference Estimation in Diffusion Models18 Aug 2026
- 2026Inference-Time Attribute Distribution Alignment for Unconditional Diffusion8 May 2026
- 2026Improved techniques for fine-tuning flow models via adjoint matching: a deterministic control pipeline7 May 2026
- 2026Adjoint Matching through the Lens of the Stochastic Maximum Principle in Optimal Control28 Mar 2026
- 2026Diffusion Controller: Framework, Algorithms and Parameterization7 Mar 2026
- 2026Continuous-time reinforcement learning: ellipticity enables model-free value function approximation6 Feb 2026
- 2026Conditional Diffusion Guidance under Hard Constraint: A Stochastic Analysis Approach5 Feb 2026
- 2026Supervised Guidance Training for Infinite-Dimensional Diffusion Models28 Jan 2026
- 2026Inference-Time Alignment for Diffusion Models via Variationally Stable Doob's Matching10 Jan 2026
7 more
- 2025Coffee: Controllable Diffusion Fine-tuning18 Nov 2025
- 2025Continuous Q-Score Matching: Diffusion Guided Reinforcement Learning for Continuous-Time Control20 Oct 2025
- 2025Schr"odinger bridge for generative AI: Soft-constrained formulation and convergence analysis13 Oct 2025
- 2025Understanding Sampler Stochasticity in Training Diffusion Models for RLHF12 Oct 2025
- 2025TR2-D2: Tree Search Guided Trajectory-Aware Fine-Tuning for Discrete Diffusion29 Sep 2025
- 2025Is RL fine-tuning harder than regression? A PDE learning approach for diffusion models2 Sep 2025
- 2025Composition and Alignment of Diffusion Models using Constrained Learning26 Aug 2025
- 2025TR2-D2: Tree Search Guided Trajectory-Aware Fine-Tuning for Discrete Diffusioncited by 14
- 2026Conditional Diffusion Guidance under Hard Constraint: A Stochastic Analysis Approachcited by 11
- 2025Composition and Alignment of Diffusion Models using Constrained Learningcited by 10
- 2025Understanding Sampler Stochasticity in Training Diffusion Models for RLHFcited by 7
- 2026Inference-Time Alignment for Diffusion Models via Variationally Stable Doob's Matchingcited by 5
- 2025Is RL fine-tuning harder than regression? A PDE learning approach for diffusion modelscited by 3
- 2026Supervised Guidance Training for Infinite-Dimensional Diffusion Modelscited by 3
- 2026Diffusion Controller: Framework, Algorithms and Parameterizationcited by 2
- 2026Inference-Time Attribute Distribution Alignment for Unconditional Diffusioncited by 2
- 2025Coffee: Controllable Diffusion Fine-tuningcited by 1
- 2026FluxLite: Inference-Time Proposal Control for Discrete Diffusion Modelscited by 1
- 2026Sobolev Regularized Score Difference Estimation in Diffusion Modelscited by 0
12 most cited of 14 All 14 (JSON)
- 2026Weighted Adjoint Matching: Finetuning Flow Matching Models with Time-Dependent Control Cost14 Oct 2026
- 2026Error-Corrected Inference-Time Scaling for Imperfect Diffusion Models1 Oct 2026
- 2026FluxLite: Inference-Time Proposal Control for Discrete Diffusion Models28 Sep 2026
- 2026Sobolev Regularized Score Difference Estimation in Diffusion Models18 Aug 2026
- 2026Inference-Time Attribute Distribution Alignment for Unconditional Diffusion8 May 2026
- 2026Diffusion Controller: Framework, Algorithms and Parameterization7 Mar 2026
- 2026Conditional Diffusion Guidance under Hard Constraint: A Stochastic Analysis Approach5 Feb 2026
- 2026Supervised Guidance Training for Infinite-Dimensional Diffusion Models28 Jan 2026
- 2026Inference-Time Alignment for Diffusion Models via Variationally Stable Doob's Matching10 Jan 2026
- 2025Coffee: Controllable Diffusion Fine-tuning18 Nov 2025
- 2025Understanding Sampler Stochasticity in Training Diffusion Models for RLHF12 Oct 2025
- 2025TR2-D2: Tree Search Guided Trajectory-Aware Fine-Tuning for Discrete Diffusion29 Sep 2025
12 newest of 14 All 14 (JSON)
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- 2025Fine-tuning Diffusion Policies with Backpropagation Through Diffusion Timesteps
- 2024Avoiding mode collapse in diffusion models fine-tuned with reinforcement learning
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- 2026A Continuous-Time Reinforcement Learning Framework for Fine-Tuning Discrete Diffusion Models
- 2023Towards Controllable Diffusion Models via Reward-Guided Exploration
- 2025Score as Action: Fine-Tuning Diffusion Generative Models by Continuous-time Reinforcement Learning
- 2026Diffusion Policy through Conditional Proximal Policy Optimization
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