La1-xSrxCuO2.5 is composed of coupled cuprate ladders, and admits hole
doping without structural alteration. It is thus a candidate novel su
perconductor, although to date superconductivity has not been found. H
ere we study the undoped, parent state to elucidate the interplay betw
een spin liquid and antiferromagnetic ground states in systems with po
tential for superconductivity.