  We construct a 2D holographic ionic lattice with hyperscaling-violating
infrared geometry and study single-electron spectral functions ("ARPES
photoemission curves") on this background. The spectra typically show a
three-peak structure, where the central peak undergoes a crossover from a sharp
but not Fermi-liquid-like quasiparticle to a wide incoherent maximum, and the
broad side peaks resemble the Hubbard bands. These findings are partially
explained by a perturbative near-horizon analysis of the bulk Dirac equation.
Comparing the holographic Green functions in imaginary frequency with the Green
functions of the Hubbard model obtained from quantum Monte Carlo, we find that
the holographic model provides a very good fit to the Hubbard Green function.
However, the information loss when transposing the holographic Green functions
to imaginary frequencies implies that a deeper connection to Hubbard-like
models remains questionable.
