Sun, 06 Jul 2008 10:57:50 BST CiteULike: dchens Baxter http://www.citeulike.org/user/dchen/author/Baxter CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dchen/article/2553074 <i>Physical Review Letters, Vol. 99, No. 2. (2007)</i><br /><br />We present measurements showing the presence and the absence of molecular chaos in a two-layer vertically vibrated granular media where a plate drives a horizontal layer of massive grains, which, in turn, drives a second horizontal layer of lighter grains above the first. In the first layer driven by the plate, the velocities are spatially correlated. In the second layer, we find uncorrelated velocities consistent with the presence of molecular chaos. In this experiment, energy injection that is randomized in both space and time throughout the shaking cycle is necessary for observing molecular chaos and “kinetic theory”-like behavior. At higher densities, excluded volume effects force velocity correlations in the system which is no longer “gaslike” in behavior. Experimental Evidence for Molecular Chaos in Granular Gases GW Baxter JS Olafsen doi:10.1103/PhysRevLett.99.028001 Physical Review Letters, Vol. 99, No. 2. (2007) 2008-03-18T22:03:56-00:00 2007 Physical Review Letters 99 2 APS 2007 grain