Memory

Summary

Critical to quantum information applications is the need to store a quantum state while other qbits are created or processed.

Description

Generation of entanglement by erasing "which-path" information with two ensembles of quantum emitters; (here, rare earth ions in a host crystal).

While photonic systems offer very robust qbits and are excellent for transporting quantum information between locations due to their minimal interactions with their environment, they are inconvenient for the storage of quantum information in one place. As a result there is significant interest in developing matter-based qbits. To implement such a system, one needs a quantum state that is accessible by some controllable means, but interacts only weakly with it surrounding environment. The nuclear hyperfine states are one such system. We are working on storing quantum information in Praseodymium (Pr) ions (doping in a crystalline matrix) which have nuclear hyperfine states with lifetimes of tens of seconds. Current efforts involve using optical beams to prepare these ions in the optimal states for long term storage and are beginning to show promising results.