On the basis of Quantum-Monte-Carlo results the evolution of the spectral weight A(k⃗, ω) of the two-dimensional Hubbard model is studied from insulating to metallic behavior. As observed in recent photoemission experiments for cuprates, the electronic excitations display essentially doping-independent features: a quasiparticle-like dispersive narrow band of width of the order of the exchange interaction J and a broad valence- and conduction-band background. The continuous evolution is traced

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... ck to one and the same many-body origin: the doping-dependent antiferromagnetic spin-spin correlation.