  Recently, it has been shown that entropy can be used to sort Brownian
particles according to their size. In particular, a combination of a static and
a time-dependent force applied on differently sized particles which are
confined in an asymmetric periodic structure can be used to separate them
efficiently, by forcing them to move in opposite directions. In this paper, we
investigate the optimization of the performance of the 'entropic splitter'.
Specifically, the splitting mechanism and how it depends on the geometry of the
channel, and the frequency and strength of the periodic forcing is analyzed.
Using numerical simulations, we demonstrate that a very efficient and fast
separation with a practically 100% purity can be achieved by a proper
optimization of the control variables. The results of this work could be useful
for a more efficient separation of dispersed phases such as DNA fragments or
colloids dependent on their size.
