title: Origin of rigidity in dry granular solids.
abstract: Solids are distinguished from fluids by their ability to resist shear. In traditional solids, the resistance to shear is associated with the emergence of broken translational symmetry as exhibited by a nonuniform density pattern. In this work, we focus on the emergence of shear rigidity in a class of solids where this paradigm is challenged. Dry granular materials have no energetically or entropically preferred density modulations. We show that, in contrast to traditional solids, the emergence of shear rigidity in these granular solids is a collective process, which is controlled solely by boundary forces, the constraints of force and torque balance, and the positivity of the contact forces. We develop a theoretical framework based on these constraints, which connects rigidity to broken translational symmetry in the space of forces, not positions of grains. We apply our theory to experimentally generated shear-jammed states and show that these states are indeed characterized by a persistent, non-uniform density modulation in force space, which emerges at the shear-jamming transition.
authors: Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02454, USA.
authors: Sumantra
authors: S
authors: Sarkar
authors: Dapeng
authors: D
authors: Bi
authors: Jie
authors: J
authors: Zhang
authors: R P
authors: RP
authors: Behringer
authors: Bulbul
authors: B
authors: Chakraborty