From Isolation to Alignment: Unified LoRA for Efficient Multi-Task Learning

Jinda Liu, Yi Chang, Yuan Wu


Abstract
Parameter-Efficient Fine-Tuning (PEFT) is essential for adapting Large Language Models (LLMs) to multi-task scenarios. A prevailing trend in this field involves complex LoRA variants with multiple adapters or heads, which rely on the premise that architectural isolation of task-specific knowledge is necessary. However, this design often introduces dynamic routing, preventing weight merging and causing significant inference latency. In this work, we present a direct challenge to this paradigm. We first reveal a paradox where a simplified, router-free multi-head model with high inter-head redundancy outperforms complex, diversity-driven baselines. Furthermore, we demonstrate that a unified, single-adapter LoRA with increased rank achieves highly competitive performance, questioning the necessity of multi-component structures. Based on these findings, we propose Align-LoRA, a unified and efficient framework that shifts the focus from architectural isolation to representation alignment. Align-LoRA incorporates an explicit alignment loss to encourage the learning of task-shared representations within a shared latent space. Crucially, our method maintains the standard LoRA architecture, ensuring zero inference latency via weight merging. Theoretical analysis and extensive experiments confirm that Align-LoRA significantly surpasses prevailing approaches, establishing a simpler, more effective, and production-friendly paradigm for multi-task PEFT. The code is available at [Align-LoRA](https://github.com/jinda-liu/Align-LoRA).
Anthology ID:
2026.findings-emnlp.146
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:
3065–3084
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.146/
DOI:
Bibkey:
Cite (ACL):
Jinda Liu, Yi Chang, and Yuan Wu. 2026. From Isolation to Alignment: Unified LoRA for Efficient Multi-Task Learning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 3065–3084, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
From Isolation to Alignment: Unified LoRA for Efficient Multi-Task Learning (Liu et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.146.pdf