Exact diagonalization for spin-1/2 spin ice pyrochlores

We present exact solutions for a 16-site spin-1/2 pyrochlore magnet with nearest neighbour exchange interactions. The methods of group theory (symmetry) are used to completely block-diagonalize the Hamiltonian, yielding precise details about the symmetry and spin structure of the eigenstates, in order to evaluate the spin ice density at finite temperature. At low enough temperatures, a quantum spin ice phase is clearly outlined within the four parameter space of the general model of exchange interactions.