cs.LGSep 28, 2026

λλ-JEPA Spectral Anti-Collapse Regularization for Self-Supervised Learning

Authors: Berker Demirel, Clémentine Dominé, Valentino Maiorca, Marco Fumero, Marco Mondelli, Francesco Locatello

Organizations: Institute of Science and Technology Austria (ISTA) Am Campus 1, 3400 Klosterneuburg, Austria

Abstract

Joint-embedding self-supervised learning typically combines an invariance objective across augmented views with additional mechanisms to prevent representational collapse. These objectives are often applied after a projection head, while downstream tasks use the backbone representation before the projector. We find that this mismatch does not necessarily prevent dimensional collapse in the backbone, which can retain low effective rank and potentially limit downstream transfer. To address this, we introduce SACReg, a spectral anti-collapse regularizer motivated by an analysis of λλ-balance, which captures the relative scale of weight matrices across layers. In a two-layer linear network, we show that (i) λλ-balance prevents collapse, and (ii) our regularizer applied to the backbone induces λλ-balance. In the nonlinear case, this regularizer leads to anti-collapse as well and, in realistic architectures on ImageNet100, it empirically increases the representations' ranks. We apply SACReg to JEPA and propose λλ-JEPA, which improves over LeJEPA and VISReg on ImageNet-1k classification and in average linear-probe transfer performance across eight downstream image datasets. On video self-supervised learning, λλ-JEPA improves over LeVJEPA and V-JEPA 2 on the Something-Something-v2 and Kinetics-400 benchmarks. Code is available at https://github.com/berkerdemirel/lambda-jepa.

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