Generalized spectral signatures of electron fractionalization in quasi-one- and two-dimensional molybdenum bronzes and superconducting cuprates

We establish the quasi-one-dimensional Li purple bronze as a photoemission paradigm of Luttinger liquid behavior. We also show that generalized signatures of electron fractionalization are present in the angle-resolved photoemission spectra for quasi-two-dimensional purple bronzes and certain cuprates. An important component of our analysis for the quasi-two-dimensional systems is the proposal of a ``melted holon'' scenario for the $\mathbf{k}$-independent background that accompanies but does not interact with the peaks that disperse to define the Fermi surface.