Casimir-like force between intruders in granular gases
  We numerically study a two-dimensional granular gas of rigid disks where an external driving force is applied to each particle in such a way that the system is driven into a steady state by balancing the energy input and the dissipation due to inelastic collisions. Two intruder particles embedded in this correlated medium experience a fluctuation-induced force -- that is itself a fluctuating quantity -- due to the confinement of the hydrodynamic fluctuations between them. We find that the probability distribution of this force is a Gaussian centered on a value that is proportional to the steady-state temperature and grows logarithmically with system size. We investigate the effect of the other relevant parameters and estimate the force using the Fourier transform of the fluctuating hydrodynamic fields. 
M. Reza Shaebani and Jalal Sarabadani