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arXiv · 2608.02347

Mamba with Hierarchical Memory: Solving Representation Bottleneck in Long Sequence Modeling

Qinwen Wang·Jieping Luo·Aoxiang Qin·Ruoyu Zhao·Jianxiong Tang·Wei Zhang·Zhichao Lu·Luziwei Leng
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Abstract

Recurrent linear attention models (RLAs) such as Mamba offer efficient linear-time sequence modeling as an alternative to Transformers, yet their fixed-capacity recurrent states limit long-sequence modeling. Drawing inspiration from hierarchical human memory, we propose Hierarchical Memory Mamba (HMM) to address this limitation. Building upon a pre-trained Mamba backbone, HMM integrates a lightweight working memory that extracts slow paragraph-level semantics (PLS) from the fast sensory memory embedded in the backbone's hidden states. The PLS is subsequently compressed into persistent long-term memory for task-relevant retrieval. The hierarchical processing of semantic information overcomes the representation bottleneck of RLAs and endows HMM cross-task generalization through parametric learning, which is not observed in other long-context enhanced Mamba variants. Evaluations on Passkey Retrieval and LongBench-E tasks demonstrate that HMM improves retrieval success by 34.3--37.1% and reasoning accuracy by 1.6--14.2% over strong Mamba-based models, while adding only 2% extra parameters and with minimal training overhead.

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Qinwen Wang, Jieping Luo, Aoxiang Qin, Ruoyu Zhao, Jianxiong Tang, Wei Zhang, Zhichao Lu, Luziwei Leng. 2026-08-03. Mamba with Hierarchical Memory: Solving Representation Bottleneck in Long Sequence Modeling. https://arxiv.org/abs/2608.02347

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