Nuclear-spin based quantum information
For quantum communication and cryptography, for networking quantum computers, and for any other applications which require quantum information to be transferred, it is essential to build a quantum network. Photons are the most efficient carriers of information, but are difficult to store for long periods of time. Atoms work well for storing quantum information, but are difficult to transfer long distances.
Techniques have been developed to transfer information back and forth between photons and ensembles of atoms. In prior work, the information was stored in the electron wavefunction of the atom. Unfortunately, the electron wavefunction is highly susceptible to decoherence from collisions and magnetic fields, which can destroy the information stored. We have applied these same techniques to the Yb-173 isotope of atomic ytterbium, enabling the storage of information in the nuclear wavefunction of the atom. The nucleus is highly isolated from the environment, and thus a favorable place to store quantum information. We have demonstrated "stopped light" using Yb-173. We achieve light storage times competitive with the world state-of-the-art, limited only by the lifetime of the Yb in our cryogenic cell.
In addition, we are investigating other nonlinear optics techniques using Yb-171 to produce nonclassical states of light.