English

Drifting Objectives for Refining Discrete Diffusion Language Models

Computation and Language 2026-05-20 v1 Machine Learning

Abstract

Discrete diffusion language models (DDLMs) generate text by iteratively denoising categorical token sequences, while recent drifting methods for continuous generators suggest that part of this sampling-time correction can instead be absorbed into training through an anti-symmetric fixed-point objective. We study how to transfer this principle to DDLMs, where the main challenge is the interface with discrete text: hard token samples are non-differentiable, and categorical predictions do not directly provide continuous samples to drift. We formulate TokenDrift, a drifting objective that lifts categorical predictions to soft-token features, applies anti-symmetric drifting in a frozen semantic space, and backpropagates the resulting stop-gradient feature target to DDLM logits. In controlled continual-training experiments with masked and uniform-state diffusion backbones, TokenDrift improves fixed-NFE generation quality over matched continuation baselines, reducing Gen.-PPL at 4 NFEs by 89% on MDLM and 86% on DUO. These results suggest that drifting can provide a practical refinement objective for DDLMs.

Keywords

Cite

@article{arxiv.2605.19470,
  title  = {Drifting Objectives for Refining Discrete Diffusion Language Models},
  author = {Daisuke Oba and Hiroki Furuta and Naoaki Okazaki},
  journal= {arXiv preprint arXiv:2605.19470},
  year   = {2026}
}

Comments

Project page: https://daioba.github.io/tokendrift/