Sum rules and density response of a two-dimensional charged Bose fluid

The density response of a two-dimensional charged Bose fluid at absolute ze ro temperature is studied beyond the random-phase approximation by includin g the many-body correlation effects. The correlations are accounted for thr ough a static local-field correction obtained by satisfying in an approxima te way the third frequency-moment sum rule of the density response function . The static structure factor, the pair-correlation function, the elementar y excitation spectrum, and the ground-state energy are calculated over a wi de range of boson number density. Wherever available, the results are compa red with the recent diffusion Monte Carlo data and the calculation based up on the theory of Singwi ct at. We also present a comparison between the res ults of electron and charged Bose fluids for pair-correlation function and elementary excitation spectrum.