A team of German physicists managed to pack the light and unpack it 1.2 millimeters away, without changing it in the process.
It is a simple concept, but extremely difficult to achieve. To do this, the team at Johannes Gutenberg University in Mainz (JGU) had to cool the rubidium-87 atoms to almost absolute zero.
“We stored the light by putting it in a suitcase, so to speak, only in our case the suitcase was made of a cloud of cold atoms,” stated Patrick Windpassinger, professor at JGU and head of research. “I moved the suitcase a short distance and then took out the light again,” he added.
The experiment could usher in a new era in quantum computing – in some systems data storage requires capturing and manipulating quantum information carried by light
The controlled handling and storage of quantum information, as well as the ability to retrieve it, are essential conditions for making progress in quantum communication and for performing appropriate computerized operations in the quantum world. Optical quantum memories, which allow the storage and retrieval of light-borne quantum information on demand, are essential for scalable quantum communications networks.
For example, they may represent important blocks of quantum repetition or instruments in linear quantum calculus. In recent years, assemblies of atoms have proven to be suitable media for storing and retrieving optical quantum information. Using a technique known as “electromagnetically induced transparency” (EIT), incident light pulses can be captured and mapped coherently to create a collective excitation of the storage atoms. Because the process is largely reversible, the light can then be recovered again with high efficiency.
“This is very interesting not only for physics in general, but also for quantum communication, because light is not very easy to ‘capture’ and, if you want to transport it elsewhere in a controlled way, it usually ends up being lose, ”he added.
Their experiment also shows that light had only a “minor effect on storage consistency,” as the team writes in a work published in the journal Physical Review Letters.
The experiment is based on previous research in which the same team managed to transport cold atoms along an “optical conveyor belt” produced by two laser beams. The team hopes that their research could one day lead to the storage of light-based memory – “optical circuit memories” – in quantum communications networks.