  In addition to self-propulsion by phoretic mechanisms that arises from an
asymmetric distribution of reactive species around a catalytic motor, spherical
particles with a uniform distribution of catalytic activity may also propel
themselves under suitable conditions. Reactive fluctuation-induced asymmetry
can give rise to transient concentration gradients which may persist under
certain conditions, giving rise to a bifurcation to self-propulsion. The nature
of this phenomenon is analyzed in detail, and particle-level simulations are
carried out to demonstrate its existence.
