  We study numerically a system of athermal, overdamped, frictionless spheres,
as in a non-Brownian suspension, in two and three dimensions. Compressing the
system isotropically at a fixed rate $\dot\epsilon$, we investigate the
critical behavior at the jamming transition. The finite compression rate
introduces a control timescale, which allows one to probe the critical
timescale associated with jamming. As was found previously for steady-state
shear-driven jamming, we find for compression-driven jamming that pressure
obeys a critical scaling relation as a function of packing fraction $\phi$ and
compression rate $\dot\epsilon$, and that the bulk viscosity $p/\dot\epsilon$
diverges upon jamming. A scaling analysis determines the critical exponents
associated with the compression-driven jamming transition. Our results suggest
that stress-isotropic, compression-driven, jamming may be in the same
universality class as stress-anisotropic, shear-driven, jamming.
