  We explore numerically the shear rheology of soft repulsive particles at
large volume fraction. The interplay between viscous dissipation and thermal
motion results in multiple rheological regimes encompassing Newtonian,
shear-thinning and yield stress regimes near the `colloidal' glass transition
when thermal fluctuations are important, crossing over to qualitatively similar
regimes near the `jamming' transition when dissipation dominates. In the
crossover regime, glass and jamming sectors coexist and give complex flow
curves. Although glass and jamming limits are characterized by similar
macroscopic flow curves, we show that they occur over distinct time and stress
scales and correspond to distinct microscopic dynamics. We propose a simple
rheological model describing the glass to jamming crossover in the flow curves,
and discuss the experimental implications of our results.
