  We introduce a novel simulation method that is designed to explore
fluctuations of the phasonic degrees of freedom in decagonal colloidal
quasicrystals. Specifically, we attain and characterise thermal equilibrium of
the phason ensemble via Monte Carlo simulations with particle motions
restricted to elementary phasonic flips. We find that, at any temperature, the
random tiling ensemble is strongly preferred over the minimum phason-strain
quasicrystal. Phasonic flips are the dominant carriers of diffusive mass
transport in physical space. Sub-diffusive transients suggest cooperative flip
behaviour on short time scales. In complementary space, particle mobility is
geometrically restricted to a thin ring around the acceptance domain, resulting
in self-confinement and persistent phasonic order.
