  We investigate the entanglement in the ground state of systems comprising two
and three qubits with random interactions. Since the Hamiltonians also contain
deterministic one-body terms, by varying the interaction strength, one can
continuously interpolate between deterministic separable eigenstates and fully
random entangled eigenstates, with non-trivial intermediate behavior.
Entanglement strongly depends on the underlying topology of the interaction
among the qubits. For a certain class of interactions GHZ entanglement is
favoured by a non-separable collective interaction, while for fully separable
pairwise interactions the ground states concentrate in the vicinity of W
states.
