  We consider a discrete version of the Atlas model, which corresponds to a
sequence of zero-range processes on a semi-infinite line, with a source at the
origin and a diverging density of particles. We show that the equilibrium
fluctuations of this model are governed by a stochastic heat equation with
Neumann boundary conditions. As a consequence, we show that the current of
particles at the origin converges to a fractional Brownian motion of Hurst
exponent H=1/4.
