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arXiv · 1811.05350

Non-equilibrium steady states, coexistence and criticality in driven quasi-two-dimensional granular matter

Thomas Schindler·Sebastian C. Kapfer
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Abstract

Nonequilibrium steady states of vibrated inelastic frictionless spheres are investigated in quasi-two-dimensional confinement via molecular dynamics simulations. The phase diagram in the density-amplitude plane exhibits a fluidlike disordered and an ordered phase with threefold symmetry, as well as phase coexistence between the two. A dynamical mechanism exists that brings about metastable traveling clusters and at the same time stable clusters with anisotropic shapes at low vibration amplitude. Moreover, there is a square bilayer state which is connected to the fluid by BKTHNY-type two-step melting with an intermediate tetratic phase. The critical behavior of the two continuous transitions is studied in detail. For the fluid-tetratic transition, critical exponents of $\tildeγ=1.73$, $η_4 \approx 1/4$, and $z=2.05$ are obtained.

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Thomas Schindler, Sebastian C. Kapfer. 2019-02-12. Non-equilibrium steady states, coexistence and criticality in driven quasi-two-dimensional granular matter. https://doi.org/10.1103/physreve.99.022902

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