The persistence exponent, theta, is defined by N_F sim t^theta, where t is
the time since the start of the coarsening process and the "no-flip fraction",
N_F, is the number of points that have not seen a change of "color" since t=0.
Here we investigate numerically the persistence exponent for a binary fluid
system where the coarsening is dominated by hydrodynamic transport. We find
that N_F follows a power law decay (as opposed to exponential) with the value
of theta somewhat dependent on the domain growth rate (L sim t^alpha, where L
is the average domain size), in the range theta=1.23 +-0.1 (alpha = 2/3) to
theta=1.37 +-0.2 (alpha=1). These alpha values correspond to the inertial and
viscous hydrodynamic regimes respectively.Comment: 9 pages RevTex, 9 figures included as eps files on last 3 pages,
submitted to Phys Rev
