The sequence of images that constitute Hollywood movies can be stored handily on solid-state media such as magnetic tape or compact diskettes. At the Joint Quantum Institute images can be stored in something as insubstantial as a gas of rubidium atoms. No one expects a vapor to compete with a solid in terms of density of storage. But when the “images” being stored are part of a quantum movie—-the coherent sequential input to or output from a quantum computer—-then the pinpoint control possible with vapor will be essential.
Last year Paul Lett and his JQI colleagues reported the ability to store a sequence of images (two letters of the alphabet) which were separated in time but overlapping in space within the volume of a gas-filled memory cell. This is random access in time. In a new experiment, by contrast, parts of a single image (spread out across a volume of space) can be stored and later recovered in chunks. Selectively reading out these partial views represents random access memory in space. The earlier storage effort could be called “temporal multiplexing,” while now it can be called “spatial multiplexing.”
Read more at: Phys.org