Trajectory Self-Feedback in Diffusion Language Models: A Systematic Survey

Yash Shah, Abhijit Chakraborty, Vivek Gupta


Abstract
Diffusion language models generate text through iterative denoising, allowing intermediate predictions to influence later denoising steps, a recurring practice we call trajectory self-feedback (TSF). TSF is adopted under inconsistent terminology, evaluated on incompatible benchmarks, and studied by disconnected communities, yet no prior review characterises it reproducibly. We present a systematic literature review under an evidence-based methodology: six pre-specified questions, a documented six-library search with snowballing, explicit selection and quality criteria, and a structured synthesis of 24 primary studies across seven clusters, with a released audit trail. We find: (i) a model-agnostic taxonomy resolves four operator families: Prediction-Space Concatenation, Confidence-weighted Path Signals, Reward-Reinforced Conditioning, and Correction-Targeted Feedback, that the literature conflates as self-conditioning; (ii) evidence of benefit is real but fragmented across incomparable settings; (iii) within our search window, no study jointly varies the TSF mechanism and measures faithfulness on knowledge-intensive tasks; and (iv) a discrete/continuous asymmetry consistent with the sampling-wall hypothesis is visible but never tested. We conclude with eight open problems, a dependency map, and review-derived diagnostics (Commitment Index, Correction Capacity) and a Standardised Evaluation Protocol (SEP-DLM) to make TSF measurable across quality, correction, trajectory commitment, and faithfulness.
Anthology ID:
2026.findings-emnlp.1739
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
37189–37208
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1739/
DOI:
10.18653/2026.findings-emnlp.1739
Bibkey:
Cite (ACL):
Yash Shah, Abhijit Chakraborty, and Vivek Gupta. 2026. Trajectory Self-Feedback in Diffusion Language Models: A Systematic Survey. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 37189–37208, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Trajectory Self-Feedback in Diffusion Language Models: A Systematic Survey (Shah et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1739.pdf