LEPO: Latent Reasoning Policy Optimization for Large Language Models

Yuyan Zhou, Jiarui Yu, Hande Dong, Zhezheng Hao, Hong Wang, Jianqing Zhang, Qiang Lin


Abstract
Recently, latent reasoning has been introduced into large language models (LLMs) to leverage rich information within a continuous space.However, without stochastic sampling, these methods inevitably collapse to deterministic inference, failing to discover diverse reasoning paths.To bridge the gap, we inject controllable stochasticity into latent reasoning via Gumbel-Softmax, restoring LLMs’ exploratory capacity and enhancing their compatibility with Reinforcement Learning (RL).Building on this, we propose **L**atent R**e**asoning **P**olicy **O**ptimization (**LEPO**), a novel framework that applies RL directly to continuous latent representations.Specifically, in rollout stage, LEPO maintains stochasticity to enable diverse trajectory sampling, while in optimization stage, LEPO constructs a unified gradient estimation for both latent representations and discrete tokens.
Anthology ID:
2026.findings-acl.707
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
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Findings
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Publisher:
Association for Computational Linguistics
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Pages:
14416–14427
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.707/
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Cite (ACL):
Yuyan Zhou, Jiarui Yu, Hande Dong, Zhezheng Hao, Hong Wang, Jianqing Zhang, and Qiang Lin. 2026. LEPO: Latent Reasoning Policy Optimization for Large Language Models. In Findings of the Association for Computational Linguistics: ACL 2026, pages 14416–14427, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
LEPO: Latent Reasoning Policy Optimization for Large Language Models (Zhou et al., Findings 2026)
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