  Star polymers are within the most topologically entangled macromolecules. For
a star to move the current theory is that one arm must retract to the branch
point. The probability of this event falls exponentially with molecular weight,
and a quicker relaxation pathway eventually takes over. With a simulation over
a hundred times faster than earlier studies, we demonstrate that the mean
square displacement scales with a power law 1/16 in time, instead of the
previously assumed zero. It suggests that star polymer motion is the result of
two linear relaxations coinciding in time. By analogy to linear polymers, which
reptate with a random walk embedded in a 3D network, we show that star polymers
relax by a random walk in a 5D network.
