  We demonstrate that a fluidized bed of hard spheres during defluidization
displays properties associated with formation of a glass. The final state is
rate dependent, and as this state is approached, the bed exhibits heterogeneity
with increasing time and length scales. The formation of a glass results in the
loss of fluidization and an arrest of macroscopic particle motion. Microscopic
motion persists in this state, but the bed can be jammed by application of a
small increase in flow rate. Thus a fluidized bed can serve as a test system
for studies of glass formation and jamming.
