Researchers at the Karlsruhe Institute of Technology (KIT) have reported important progress in quantum physics and materials science by optically initializing, controlling, and reading out nuclear spin states in a molecular material for the first time. Because of their weak interaction with the environment, nuclear spins are particularly stable quantum information carriers. The research, published in Nature Materials, shows that molecular nuclear spins could be a promising building block for future quantum technologies.
Nuclear magnetic resonance (NMR) is an established method for analyzing materials and molecules, with applications ranging from chemical analysis to quantum information processing. For a new paper, KIT researchers analyzed a molecular crystal containing europium ions. Such ions have especially narrow optical transitions that allow direct addressing of nuclear spin states. Using laser light, they were able to initialize nuclear spins in defined states and then read out those states.
In addition to optical addressing, the researchers used high-frequency fields to control the spins and protect them from interfering environmental influences. They achieved nuclear spin quantum coherence with a lifetime of up to two milliseconds, an interval during which a quantum system maintains a precisely defined quantum mechanical state.








