We show that slave particles are always confined in $\mathrm{U}\left(1\right)$ gauge theories of interacting electron systems. Consequently, the low-lying degrees of freedom are different from the slave particles. This is done by constructing a dual formulation of the slave-particle representation in which the no-double-occupancy constraint becomes linear and, hence, soluble. Spin-charge separation, if it occurs, is due to the existence of solitons with fractional quantum numbers in a particular dual action.

• Received 17 December 1999

DOI:https://doi.org/10.1103/PhysRevLett.85.178