  The fluctuating hydrodynamics by Brey et. al. is analytically solved to get
the long-time limit of the fluctuations of the number density, velocity field,
and energy density around the homogeneous cooling state of a granular gas,
under physical conditions where it keeps stable. Explicit expressions are given
for the non-white contributions in the elastic limit. For small dissipation,
the latter is shown to be much smaller than the inelastic contributions, in
general. The fluctuation-induced Casimir-like forces on the walls of the system
are calculated assuming a fluctuating pressure tensor resulting from perturbing
its Navier-Stokes expression. This way, the Casimir-like forces emerges as the
correlation between the longitudinal velocity and the energy density.
Interestingly, the fluctuation-induced forces push/pull the system towards the
square or rectangular geometry when they vanish, in good agreement with the
event-driven numerical simulations.
