Incollection,
Insights into disorder: the structure of granular materials
Abstract Book of the XXIII IUPAP International Conference on Statistical Physics, Genova, Italy, (9-13 July 2007)
Abstract
In this talk I discuss the open and controversial issue of whether the properties of complex materials such as granular matter can be described in terms of a few simple quantities. In order to answer this question I look inside granular materials by means of X-ray computed tomography. These studies have produced the world-largest database on disordered and complex structures 1. Such a database has been used to perform analysis on the structure of granular matter at rest and on its configurational fluctuations during evolution 2,3. We have established the existence of four density regions 3 and we have shown that the statistical fluctuations of the local structure can be quantitatively predicted with good precision by means of a deductive statistical mechanics approach 2,4 (see Figure 1). These studies have also important implications on the concept of granular temperature and they have great relevance for the validation of statistical mechanics descriptions of these systems.
1) T. Aste, M. Saadatfar ,T.J. Senden, ``Geometrical structure of disordered sphere packings, Phys. Rev. E 71 (2005) 061302.\\
2) T. Aste, ``Volume fluctuations and geometrical constraints in granular packs, Phys. Rev. Lett. 96 (2006) 018002.\\
3) T. Aste, ``Variations around disordered closed packings, Journal of Physics Condensed Matter 17 (2005) S2361--S2390.\\
4) T. Aste, T. Di Matteo, M Saadatfar, T. J. Senden, M. Schroter and H. L. Swinney, ``An invariant distribution in static granular media, cond-mat/0612063.
