Molecular nanomagnets with competing interactions as optimal units for qudit-based quantum computation

Quantum systems displaying many accessible levels could be very powerful units of forthcoming quantum computing architectures. Indeed, the large number available states significantly simplify actual implementation several algorithms. Here we show that artificial molecular spins are particularly suitable to realize such a platform. In particular, multispin molecules with competing interactions provide low-energy multiplets in which decoherence is strongly suppressed compared single spin $S$ and does not increase system size. This feature, combined proper connectivity between multiplets, enables complex operations remarkable fidelity, thus fully unleashing potential approach. We demonstrate power this approach by numerically simulating one- two-qudit gates on realistic systems.