Spectral Archaeology: The Causal Topology of Model Evolution

arXiv:2601.03424v1 Announce Type: new Abstract: Behavioral benchmarks tell us \textit{what} a model does, but not \textit{how}. We introduce a training-free mechanistic probe using attention-graph spectra. Treating each layer as a token graph, we compute algebraic connectivity ($\lambda_2$), smooth…