Schröter, MatthiasGoldman, Daniel ISwinney, Harry L2020-02-182020-02-182005-03-301539-37551550-2376https://hdl.handle.net/10161/20168A statistical description of static granular material requires ergodic sampling of the phase space spanned by the different configurations of the particles. We periodically fluidize a column of glass beads and find that the sequence of volume fractions phi of postfluidized states is history independent and Gaussian distributed about a stationary state. The standard deviation of phi exhibits, as a function of phi, a minimum corresponding to a maximum in the number of statistically independent regions. Measurements of the fluctuations enable us to determine the compactivity X , a temperaturelike state variable introduced in the statistical theory of Edwards and Oakeshott [Physica A 157, 1080 (1989)].Science & TechnologyPhysical SciencesPhysics, Fluids & PlasmasPhysics, MathematicalPhysicsSTATISTICAL-MECHANICSFLUIDIZED-BEDSDYNAMICSPOWDERSMODELCOMPACTIONMIXTURESPACKINGSPHERESJournal article2020-02-18