Time-of-flight images of Mott insulators in the Hofstadter-Bose-Hubbard model

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 approach against those of the strong-coupling expansion for the Landau and symmetric gauges, we find pronounced corrections to the former results, which is a clear manifestation of the critical role played by quantum fluctuations in two dimensions.