Geometric phase in coupled bipartite systems PRL 92,150406(2004),by X.X. yi etal H=ao, B()+J(o o2+hcD 13C 130 B(0=Bo(Sin 8 cos o, sin Asind, cos 0) Schematic of trichloroethylene a typical molecule used for QIP ·a2+hc.11 Geometric phase in coupled bipartite systems 1 1 2 1 ( ) ( . .) 2 H B t J h c    + + =  + + PRL 92,150406(2004),by X. X. Yi etal. Schematic of trichloroethylene, a typical molecule used for QIP. 0 B t B ( ) (sin cos ,sin sin ,cos ) =      1 2 . . z z   + h c