Flux tubes, visons, and vortices in spin-charge separated superconductors

The idea of spin-charge separation in cuprate superconductors has been recently energized by Senthil and Fisher who formulated a Z(2) gauge theory and, within its context, proposed a "vison detection" experiment as a test for topological order in a sample with multiply connected geometry. Here we show that the same experiment can be performed to test for the spin-charge separation in U(1) (but not in SU(2)) theory and argue that vortex core spectroscopy can in fact distinguish between the different symmetries of the fictitious gauge field. (C) 2001 Elsevier Science B.V. All rights reserved.