Diffusion LM research timeline

Seven reading anchors for understanding method differences, followed by the recorded publication corpus.

These are selected 2021–2025 reading anchors, not a complete history or ranking. The comparisons below do not establish influence between papers.

First arXiv submission defines the order, not priority, first public disclosure, conference acceptance or code release. Explanations refer to the separately pinned source revision: not every detail necessarily appeared in v1.

Jump to recorded papers · Observed source and code changes · Learning routes

Source-linked reading anchors

  1. Structured Denoising Diffusion Models in Discrete State-Spaces

    · arXiv v1

    D3PM describes corruption through transition matrices over discrete states, including absorbing masks.

    Limits and method comparison

    A foundation for categorical data, not a text-only method. Transition choices must be checked for the target data.

    Compare a general family of discrete transitions with MDLM’s mask-specific construction. mdlm.

    Summary source · v3 · Find in corpus · Masked / discrete diffusion

  2. Diffusion-LM Improves Controllable Text Generation

    · arXiv v1

    Diffusion-LM denoises real-valued word representations; continuous intermediate variables support gradient-based text control.

    Limits and method comparison

    Continuous word representations are not automatically compressed autoencoder latents. Control after decoding is not a hard guarantee.

    Unlike D3PM’s discrete state space, this denoising trajectory operates on real-valued vectors. d3pm.

    Summary source · v1 · Find in corpus · Controllability

  3. DiffuSeq: Sequence to Sequence Text Generation with Diffusion Models

    · arXiv v1

    DiffuSeq uses continuous-representation diffusion for conditional sequence-to-sequence generation, with partial noising and source conditioning.

    Limits and method comparison

    Read this as conditional Seq2Seq. The original paper is distinct from the later DiffuSeq-v2 work.

    Both use continuous representations; source-conditioned Seq2Seq and gradient-based attribute control are different tasks. diffusion-lm.

    Summary source · v3 · Find in corpus · Controllability

  4. Discrete Diffusion Modeling by Estimating the Ratios of the Data Distribution

    · arXiv v1

    SEDD introduces score entropy to learn probability ratios between discrete states and applies it to language modelling.

    Limits and method comparison

    Continuous time does not make token states continuous. Sampling quality and measured serving latency require separate evidence.

    Compare the probability-ratio objective with D3PM’s transition-matrix design; these are different components of a discrete model. d3pm.

    Summary source · v3 · Find in corpus · Masked / discrete diffusion

  5. Simple and Effective Masked Diffusion Language Models

    · arXiv v1

    MDLM specializes discrete diffusion to masking and derives a simplified mixture of masked-language-model losses, with several sampling choices.

    Limits and method comparison

    Masking is one discrete corruption family. Keep the training objective separate from the selected sampler.

    Compare MDLM’s mask-specific formulation with SEDD’s probability-ratio view; shared discrete states do not imply identical losses. sedd.

    Summary source · v2 · Find in corpus · Masked / discrete diffusion

  6. Large Language Diffusion Models

    · arXiv v1

    LLaDA trains a Transformer to predict masked tokens through pre-training and supervised fine-tuning; reverse generation iteratively fills masks.

    Limits and method comparison

    This remains a discrete-token model. Reported scale and task performance do not establish universal superiority or latency.

    Both use masked tokens; compare LLaDA’s pre-training/SFT setup with MDLM’s objective and sampling recipe under matched conditions. mdlm.

    Summary source · v3 · Find in corpus · Post-training

  7. Block Diffusion: Interpolating Between Autoregressive and Diffusion Language Models

    · arXiv v1

    Block Diffusion is autoregressive across blocks and uses discrete diffusion inside each conditional block.

    Limits and method comparison

    Parallel token updates within a block do not remove dependencies between blocks. Latency still needs a matched measurement protocol.

    Compare block-level sequence factorization with MDLM’s masked denoising and semi-autoregressive sampling choices. mdlm.

    Summary source · v3 · Find in corpus · Inference acceleration

Recorded corpus publications

Filters below apply only to recorded papers, not the seven anchors above. These use publication dates in UTC, not site-observation dates or an importance ranking. New records appear when a checked snapshot is published.

Latest papers · Selection methodology

2026-09-07T07:55:40+00:00 · Post-training · Source

In-Place Instruction Following in Diffusion Language Models

Diffusion Large Language Models (dLLMs) generate text via bidirectional iterative denoising, naturally supporting user-specified constraints anchored at arbitrary output positions, a paradigm known as In-place Prompting (IPP). We formalize this as the In-place Instruction Following (IIF) task and construct IIF-Bench, a hierarchical benchmark spanning literal, style, and discourse-function constraints, paired with a rubric-based local-global evaluation protocol. An inference-time attention-bias probe suggests that vanilla dLLMs often under-prioritize constraint spans during denoising. We then p

Useful for: The approach applies to diffusion large language models supporting user-specified constraints at arbitrary output positions. · Limitation: Vanilla dLLMs often under-prioritize constraint spans during denoising.

2026-09-06T01:09:14+00:00 · unclassified · Source

A Ticket from Marginals to Joints: Coupled-Noise Distillation for One-Step Block Generation in Diffusion Language Models

Autoregressive language models commit one token per forward pass; diffusion language models commit a block of tokens over several steps. We ask whether a block can be committed in a single forward pass. We study this with a noise-conditioned masked denoiser: a data-independent Gaussian noise field is added to the mask embeddings so that, in principle, each sampled field selects one joint mode of the block. The established way of training such a model is to sample several fields per example and let them compete for the data, by winner-take-all or importance weighting. This gives the noise only

Useful for: The method applies to one-step block generation with one forward pass per block. · Limitation: The source does not provide quantitative results or specify the tested model sizes.

2026-09-02T04:52:01+00:00 · unclassified · Source

Predict, Don't Iterate: Efficient Adaptive-Length Infilling for Diffusion Language Models

Diffusion language models (DLMs) have emerged as a promising alternative to the auto-regressive paradigm. With bidirectional attention and any-order generation, DLMs naturally fit infilling tasks, which require generating a middle span conditioned on both the prefix and the suffix. However, infilling is sensitive to the length of the span, while DLMs require the length to be fixed before generation. Although prior studies extend DLMs to dynamic lengths, they still suffer from two limitations. (i) Sensitivity to initial length. These methods require a preset length to initialize the search and

Useful for: Infilling tasks for diffusion language models, including code and text benchmarks. · Limitation: The source does not provide detailed algorithmic implementation or per-benchmark results.

2026-09-01T08:07:21+00:00 · Post-training · Source

Membership Inference in Fine-tuned Diffusion Language Models via Token-level Memorization Asymmetry

Diffusion language models (DLMs) have recently emerged as an alternative modeling paradigm to autoregressive LMs, offering advantages such as parallel generation and bidirectional context modeling. Despite growing interest in their generative capabilities, the privacy risks of DLMs remain underexplored. We identify a phenomenon termed token-level memorization asymmetry through theoretical analysis of diffusion training dynamics. Building on this finding, we propose Q-Skew, a quantile-weighted skewness-based indicator for membership inference on finetuned DLMs. Experiments across multiple fine-

Useful for: Not assessed · Limitation: Not assessed

2026-08-31T23:50:31+00:00 · Masked / discrete diffusion · Source

Beyond Token Positions: Safety Alignment Across Denoising Steps in Diffusion Language Models

Diffusion large language models (dLLMs) generate text through iterative denoising rather than left-to-right decoding. This generation paradigm introduces two axes that can influence safety alignment: when tokens are generated during denoising and where they appear in the response. In this paper, we measure dLLM safety behavior under harmful prompts by tracing intermediate token distributions and commitment decisions throughout denoising. Our analysis shows that refusal signals are concentrated in early denoising steps and leading response positions, and the tokens committed early can strongly

Useful for: Not assessed · Limitation: Not assessed

2026-08-31T15:00:30+00:00 · Masked / discrete diffusion, Reasoning, Code generation · Source

CARVE: Verified Expansion for Variable-Length Generation in Diffusion Language Models

Masked diffusion language models predict tokens from a partially observed response canvas, enabling bidirectional conditioning and parallel token refinement. Yet standard masked-diffusion decoders use a rigid inference interface: the number of masked positions allocated to the answer is fixed before generation begins. Choosing this length is difficult. A short canvas can truncate reasoning or code, while a long canvas wastes computation and can perturb denoising. We introduce CARVE (Counterfactual-Aware Reveal with Verified Expansion), a training-free variable-length algorithm for masked diffu

Useful for: Not assessed · Limitation: Not assessed

2026-08-20T14:52:17+00:00 · Masked / discrete diffusion · Source

Discrete Diffusion Inference-Time Control with Nested Sequential Monte Carlo

We study inference-time control for text generation in discrete diffusion language models, where the goal is to steer sampling toward sequence-level rewards without retraining. Prior work in this domain has focused on particle-based methods such as best-of-$n$ sampling and bootstrap sequential Monte Carlo, which may suffer from overoptimism and weight degeneracy, respectively. We address these limitations using \emph{nested} sequential Monte Carlo methods. We formulate nested SMC (NSMC) and fully-adapted nested SMC (FA-NSMC) for Feynman--Kac steering, identifying and correcting errors in prior

Useful for: Not assessed · Limitation: Not assessed

2026-08-12T07:32:29+00:00 · Inference acceleration, Reasoning · Source

Ripple-Pivot Search: Active Parallel Decoding for Diffusion Large Language Models

Diffusion Large Language Models (dLLMs) have emerged as a competitive alternative to autoregressive language models, offering the potential for substantially faster inference through parallel decoding. Existing parallel decoding schedulers typically commit positions only after they meet a per-position criterion, overlooking how early commitments may benefit subsequent decoding. We identify a ripple effect in dLLM decoding: proactively committing a mid-entropy pivot position can induce a pronounced reduction in uncertainty across the remaining masked positions. This uncertainty reduction allows

Useful for: Not assessed · Limitation: Not assessed

2026-08-10T10:52:20+00:00 · Masked / discrete diffusion · Source

Reducing Pretraining-Generation Mismatch in Diffusion Language Models

Autoregressive language models align training and use: generation conditions on a clean prompt, and training predicts future tokens from clean left context. Diffusion language models offer parallel denoising, but native dLLM pretraining can randomly corrupt prompt and continuation tokens together, weakening the clean-prefix interface needed for prompt-conditioned generation. We identify this mismatch for prompt continuation and propose PCD (Prefix-Conditioned Diffusion), a pretraining objective that combines AR prefix supervision with no-shift suffix denoising. At the training-objective level,

Useful for: Not assessed · Limitation: Not assessed

2026-08-09T16:13:46+00:00 · unclassified · Source

Unsure but Certain: Uncovering the Representation-Confidence Gap in Diffusion Language Models

Diffusion language models use broad context to create text, suggesting they might handle input noise better than standard models. Testing reveals this is only partially true. Internally, diffusion models detect text errors highly accurately. Externally, their reported certainty ignores this signal. As accuracy drops due to noise, confidence stays near its maximum and the ability to correctly rank answers degrades toward random chance. We call this mismatch the representation confidence gap. The visible concentration of high certainty scores is a misleading surface symptom. Standard math adjust

Useful for: Not assessed · Limitation: Not assessed

2026-08-08T12:13:10+00:00 · Inference acceleration · Source

Archer: Adaptive Reuse of Cached Hidden States for Efficient Rollback in Diffusion Language Models

Diffusion language models (DLMs) iteratively refine a sequence, allowing earlier predictions to be revised as context evolves. This rollback capability distinguishes them from irreversible autoregressive generation, but makes inference costly. Every denoising update alters the global context, forcing both prompt and response states to be recomputed even though only response tokens are revisable. Key-value (KV) caching could reduce this cost, yet conventional caching assumes immutable historical states and is therefore difficult to reconcile with rollback. In this paper, we introduce Adaptive R

Useful for: Not assessed · Limitation: Not assessed

2026-08-08T11:59:38+00:00 · Masked / discrete diffusion, Controllability · Source

Commitment Before Realization: When Classifier-Free Guidance Becomes Unnecessary in Masked Diffusion Language Models

Classifier-free guidance (CFG) is usually kept on throughout masked diffusion language model decoding, although its benefit varies across prompts and over time. We study when CFG is actually needed by comparing, from any partial output, the probability of eventual constraint satisfaction under continued CFG and under base-only continuation. Their difference defines the remaining value of guidance. Guidance dependence is highly prompt-specific. Many prompts already succeed without CFG, while for others it provides no measurable benefit or can be harmful. For prompts that do benefit, the gain is

Useful for: Not assessed · Limitation: Not assessed

2026-08-06T22:34:20+00:00 · Masked / discrete diffusion, Inference acceleration, Post-training · Source

Retrofitting Linear Attention into Diffusion Language Models

Diffusion language models (dLLMs) offer a promising alternative to autoregressive models by accelerating inference through parallel decoding. Recent dLLMs commonly use blockwise semi-autoregressive decoding, generating blocks autoregressively while denoising tokens within each active block in parallel. However, despite KV caching, each denoising step still attends to all previous blocks, repeatedly incurring prefix-attention cost. Motivated by this bottleneck, we ask whether dLLM inference can be further accelerated by linearizing attention over previous blocks. We introduce block-hybrid atten

Useful for: Not assessed · Limitation: Not assessed

2026-08-06T19:23:32+00:00 · Masked / discrete diffusion · Source

Lost in Interpolation: Why Predictive Feedback Fails in Diffusion Language Models

Soft-masking accelerates the convergence of Masked Diffusion Language Models (MDLMs). Existing formulations build this blend with linear interpolation (LERP) in the raw embedding space, which implicitly treats that space as Euclidean. We analyze the embedding space of MDLMs and find that the mask and predicted-token embeddings maintain a near-constant angle of (\approx 73^\circ) throughout training, while embedding norms remain essentially flat across vocabulary-frequency rank. These indicate a hyperspherical geometry, for which LERP is the wrong interpolation primitive. We introduce Spherical

Useful for: Not assessed · Limitation: Not assessed

2026-08-04T14:54:14+00:00 · Masked / discrete diffusion, Post-training · Source

MDLMPE: Distribution Aware Positional Encoding for Masked Diffusion Language Models

Masked diffusion language models (MDLMs) enable parallel generation and bidirectional context modeling, but their positional context differs fundamentally from that of autoregressive (AR) models. Whereas AR decoding exposes a contiguous prefix, MDLM denoising produces dynamic, non-contiguous configurations of revealed and masked tokens. Conventional positional encodings such as RoPE capture sequence order and pairwise displacement but remain insensitive to this evolving token-availability structure. To address this limitation, we propose MDLMPE, a positional encoding designed specifically for

Useful for: Not assessed · Limitation: Not assessed

2026-08-04T10:53:02+00:00 · Masked / discrete diffusion, Reasoning, Post-training · Source

LLaDA MoE v2: Scaling Mixture-of-Experts Diffusion Language Models

Diffusion language models (dLLMs) offer an alternative to autoregressive (AR) language modeling, yet the scaling behavior of Mixture-of-Experts (MoE) dLLMs remains poorly understood. We systematically characterize how optimization hyperparameters, compute allocation, and architecture scale for MoE dLLMs, identifying quantitative differences from scaling trends previously reported for AR models. Specifically, for optimization, the optimal nominal batch size grows faster, while the optimal learning rate decays more rapidly with compute. For model--data allocation, IsoFLOP analysis reveals a slig

Useful for: Not assessed · Limitation: Not assessed

2026-08-03T23:09:43+00:00 · Reasoning · Source

OPTD: On-Policy Transition Distillation with Consistency-Guided Adaptive Compression for Few-Step Diffusion Language Models

Diffusion language models (dLLMs) can predict many tokens in parallel, but accurate generation still requires many iterative denoising steps. Few-step distillation accelerates decoding by compressing multiple teacher steps into a single student transition. However, existing methods construct supervision on off-policy trajectories. At inference, the student's early parallel commitments alter the context of later predictions, so the states it actually visits drift away from the supervised ones--precisely when step compression is most aggressive. On-policy distillation is a natural remedy fo

Useful for: Not assessed · Limitation: Not assessed

2026-08-03T17:59:50+00:00 · Latent diffusion · Source

AURORA-LM: Autoencoding Unified Representation for Continuous-Latent Diffusion Language Modeling

Language remains an outlier in generative modeling: while images, video, and audio are increasingly modeled in continuous latent spaces, text generation still relies predominantly on discrete tokens. Existing continuous language models either inherit embedding spaces not designed for joint generation and decoding, or compress autoencoded latents to ease diffusion, sacrificing token-level fidelity. Instead of simplifying the representation to suit the generative model, we preserve a high-capacity, decodable text latent and design the diffusion model to learn its distribution directly. We intr

Useful for: Not assessed · Limitation: Not assessed

2026-08-03T06:59:06+00:00 · Masked / discrete diffusion · Source

REFLEX: Rethinking MoE Inference as Refinement-Aware Compute Allocation in Diffusion Language Models

Mixture-of-experts (MoE) models increase parameter capacity by activating only a small subset of experts for each token. This conditional-computation paradigm has enabled autoregressive language models to scale model capacity without a proportional increase in per-token computation. In diffusion language models (DLMs), however, each denoising forward jointly revisits all token positions despite their sharply different refinement demands, while the default fixed token-choice routing assigns them a uniform expert budget, creating a mismatch between expert computation and refinement demand. We ar

Useful for: Not assessed · Limitation: Not assessed

2026-08-03T05:28:37+00:00 · Post-training · Source

Beyond On-Policy Exploration: Integrating External Policy Rollouts for Reinforcement Learning in Diffusion Language Models

Recent reinforcement learning methods for diffusion large language models (dLLMs) commonly rely on on-policy rollouts generated by the target dLLM itself. When successful on-policy rollouts are scarce, however, on-policy training may receive little positive reward and make only limited progress. To mitigate this problem, we explore incorporating higher-reward rollouts generated by a stronger external policy alongside on-policy rollouts from the target dLLM. However, directly incorporating these external rollouts introduces two practical challenges: differences in rollout length and instability

Useful for: Not assessed · Limitation: Not assessed

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