Continuous transformation of a-1/2 wedge disclination line to a+1/2 one

It is known that, in the order-parameter space S-2/Z(2) (a typical example being a uniaxial nematic liquid crystal in three dimensions), a -1/2 wedge disclination line and a +1/2 one are topologically equivalent and can thus be transformed continuously into each other. Here we report the realization of this transformation in a simulation of a cholesteric blue phase under an electric field.