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Main Authors: Deng, Huilin, Luo, Hongchen, Zhu, Yue, Li, Long, Chen, Zhuoyue, Zhao, Xinghao, Li, Ming, Zhang, Jihai, Wang, Mengchang, Cao, Yang, Kang, Yu
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2601.05870
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author Deng, Huilin
Luo, Hongchen
Zhu, Yue
Li, Long
Chen, Zhuoyue
Zhao, Xinghao
Li, Ming
Zhang, Jihai
Wang, Mengchang
Cao, Yang
Kang, Yu
author_facet Deng, Huilin
Luo, Hongchen
Zhu, Yue
Li, Long
Chen, Zhuoyue
Zhao, Xinghao
Li, Ming
Zhang, Jihai
Wang, Mengchang
Cao, Yang
Kang, Yu
contents Recent advances in Reinforcement Learning with Verifiable Rewards (RLVR) for Large Language Model (LLM) reasoning have been hindered by a persistent challenge: exploration collapse. The semantic homogeneity of random rollouts often traps models in narrow, over-optimized behaviors. While existing methods leverage policy entropy to encourage exploration, they face inherent limitations. Global entropy regularization is susceptible to reward hacking, which can induce meaningless verbosity, whereas local token-selective updates struggle with the strong inductive bias of pre-trained models. To address this, we propose Latent Policy Optimization via Iterative Information Bottleneck (IIB-LPO), a novel approach that shifts exploration from statistical perturbation of token distributions to topological branching of reasoning trajectories. IIB-LPO triggers latent branching at high-entropy states to diversify reasoning paths and employs the Information Bottleneck principle both as a trajectory filter and a self-reward mechanism, ensuring concise and informative exploration. Empirical results across four mathematical reasoning benchmarks demonstrate that IIB-LPO achieves state-of-the-art performance, surpassing prior methods by margins of up to 5.3% in accuracy and 7.4% in diversity metrics.
format Preprint
id arxiv_https___arxiv_org_abs_2601_05870
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle IIB-LPO: Latent Policy Optimization via Iterative Information Bottleneck
Deng, Huilin
Luo, Hongchen
Zhu, Yue
Li, Long
Chen, Zhuoyue
Zhao, Xinghao
Li, Ming
Zhang, Jihai
Wang, Mengchang
Cao, Yang
Kang, Yu
Machine Learning
Artificial Intelligence
Recent advances in Reinforcement Learning with Verifiable Rewards (RLVR) for Large Language Model (LLM) reasoning have been hindered by a persistent challenge: exploration collapse. The semantic homogeneity of random rollouts often traps models in narrow, over-optimized behaviors. While existing methods leverage policy entropy to encourage exploration, they face inherent limitations. Global entropy regularization is susceptible to reward hacking, which can induce meaningless verbosity, whereas local token-selective updates struggle with the strong inductive bias of pre-trained models. To address this, we propose Latent Policy Optimization via Iterative Information Bottleneck (IIB-LPO), a novel approach that shifts exploration from statistical perturbation of token distributions to topological branching of reasoning trajectories. IIB-LPO triggers latent branching at high-entropy states to diversify reasoning paths and employs the Information Bottleneck principle both as a trajectory filter and a self-reward mechanism, ensuring concise and informative exploration. Empirical results across four mathematical reasoning benchmarks demonstrate that IIB-LPO achieves state-of-the-art performance, surpassing prior methods by margins of up to 5.3% in accuracy and 7.4% in diversity metrics.
title IIB-LPO: Latent Policy Optimization via Iterative Information Bottleneck
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2601.05870