title: Jamming and fluctuations in granular drag
abstract: We investigate the dynamic evolution of jamming in granular media through fluctuations in the granular drag force. The successive collapse and formation of jammed states give a stick-slip nature to the fluctuations which is independent of the contact surface between the grains and the dragged object, thus implying that the stress-induced collapse is nucleated in the bulk of the granular sample. We also find that while the fluctuations are periodic at small depths, they become "stepped" at large depths, a transition which we interpret as a consequence of the long-range nature of the force chains.
authors.affiliation: Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA.
authors.initials: I
authors.lastname: Albert
authors.initials: P
authors.lastname: Tegzes
authors.initials: B
authors.lastname: Kahng
authors.initials: R
authors.lastname: Albert
authors.initials: JG
authors.lastname: Sample
authors.initials: M
authors.lastname: Pfeifer
authors.initials: A
authors.lastname: Barabasi
authors.initials: T
authors.lastname: Vicsek
authors.initials: P
authors.lastname: Schiffer