Exploiting Quantum Effects in Electron-Nuclear Coupled Molecular Spin Systems

Molecular spin systems coupled with nuclear spins are introduced as promising matter spin qubits in quantum information processing and quantum computing (QC). Introductory remarks are given for nonspecialists. For this purpose, NMR-based QC is described and an approach to QC exploiting electron-nuclear coupled molecular systems is given. Requisites for qubits are described as DiVincenzo's criteria. Since Shor's quantum algorithm appeared, the first successful QC experiment was carried out by highly sophisticated pulsed NMR techniques, and this very attempt brought quantum computers down to earth. It has been claimed, nevertheless, that quantum entanglement as the heart of QC has not been established in any experiments in solution. Thus, advantages of QC experiments with molecular spins over the counterparts of NMR QC are described. Quantum computing (QC) experiments with molecular spins are exemplified for a few qubits.