  We analyze the momentum distribution function and its artificial-gauge-field
dependence for the Mott insulator phases of the Hofstadter-Bose-Hubbard model.
By benchmarking the results of the random-phase approximation (RPA) approach
against those of the strong-coupling expansion (SCE) for the Landau and
symmetric gauges, we find pronounced corrections to the former results in two
dimensions.
