  Short-range correlations in 4He are investigated using many-body wave
functions obtained in the no-core shell model. The similarity renormalization
group (SRG) is used to evolve the Argonne V8' interaction and the density
operators. The effects of short-range correlations are reflected in the
two-body densities in coordinate space as a function of the distance between
two nucleons, or alternatively in in momentum space as function of the relative
momentum between two nucleons. The SRG transformation is performed in two-body
approximation. The importance of missing three-body and higher-body
contributions is investigated by comparing results obtained for different flow
parameters and by comparing to exact results with the bare Argonne V8'
interaction obtained in the correlated Gaussian approach.
