Quantum Monte Carlo Simulation of the Trellis Lattice Heisenberg Model for SrCu_{<b> 2</b>}O_{<b> 3</b>} and CaV_{<b> 2</b>}O_{<b> 5</b>}

Abstract

We study the spin-1/2 trellis lattice Heisenberg model, a coupled spin ladder system, both by perturbation around the dimer limit and by quantum Monte Carlo simulations. We discuss the influence of the inter-ladder coupling on the spin gap and the dispersion, and present results for the temperature dependence of the uniform susceptibility. The latter was found to be parameterized well by a mean-field type scaling ansatz. Finally we discuss fits of experimental measurements on SrCu$_2$O$_3$ and CaV$_2$O$_5$ to our results.