Quantum Monte Carlo simulations of a giant magnetic molecule with a S = 91 spin ground state

I will describe the basic idea of Monte Carlo simulations for statistical physics, and how these ideas can be applied to complex system of interacting quantum spins.  I will specifically discuss a recent application where we used Quantum Monte Carlo simulations to analyze a giant {Ni₂₁Gd₂₀} molecular cage with a remarkable S = 91 spin ground state.