Ground state of coupled spin-half ladders

Abstract The ground state of an array of coupled, spin-half, antiferromagnetic ladders is studied using the Green's function Monte Carlo technique. Our results clearly indicate the occurrence of a zero-temperature phase transition between a Neel ordered and a non-magnetic phase at a finite value of the inter-ladder coupling (αc≃0.3). This transition is marked by remarkable changes in the structure of the excitation spectrum.