Fluid-like behavior of a one-dimensional granular gas

We study the properties of a one-dimensional (1D) granular gas consisting of $N$ hard rods on a line of length $L$ (with periodic boundary conditions). The particles collide inelastically and are fluidized by a heat bath at temperature $Tb$ and viscosity γ. The analysis is supported by molecular dynamics simulations. The average properties of the system are first discussed, focusing on the relations between granular temperature $Tg=m〈v2〉,$ kinetic pressure, and density $ρ=N/L.$ Thereafter, we consider the fluctuations around the average behavior obtaining a slightly non-Gaussian behavior of the velocity distributions and a spatially correlated velocity field; the density field displays clustering: this is reflected in the structure factor which has a peak in the $k∼0$ region suggesting an analogy between inelastic hard core interactions and an effective attractive potential. Finally, we study the transport properties, showing the typical subdiffusive behavior of 1D stochastically driven systems, i.e., $〈|x(t)−x(0)|2〉∼Dt1/2,$ where $D$ for the inelastic fluid is larger than the elastic case. This is directly related to the peak of the structure factor at small wave vectors.