  We study the rheology of amorphous packings of soft, frictionless particles
close to jamming. Implementing a quasistatic simulation method we generate a
well defined ensemble of states that directly samples the system at its
yield-stress. A continuous jamming transition from a freely-flowing state to a
yield stress situation takes place at a well defined packing fraction, where
the scaling laws characteristic of isostatic solids are observed. We propose
that long-range correlations observed below the transition are dominated by
this isostatic point, while those that are observed above the transition are
characteristic of dense, disordered elastic media.
