  Quantum measurement is universal for quantum computation. The model of
quantum computation introduced by Nielsen and further developed by Leung relies
on a generalized form of teleportation. In order to simulate any n-qubit
unitary transformation with this model, 4 auxiliary qubits are required.
Moreover Leung exhibited a universal family of observables composed of 4
two-qubit measurements. We introduce a model of quantum computation via
measurements only, relying on state transfer: state transfer only retains the
part of teleportation which is necessary for computating. In order to simulate
any n-qubit unitary transformation with this new model, only one auxiliary
qubit is required. Moreover we exhibit a universal family of observables
composed of 3 one-qubit measurements and only one two-qubit measurement. This
model improves those of Nielsen and Leung in terms of both the number of
auxiliary qubits and the number of two-qubit measurements required for quantum
universality. In both cases, the minimal amounts of necessary resources are now
reached: one auxiliary qubit (because measurement is destructive) and one
two-qubit measurement (for creating entanglement).
