16 February 2012
US universities look to untangle the challenges of creating quantum memories
Seven US universities are collaborating to determine the best approach for generating quantum memories based on interaction between light and matter. The five year project is being funded by an $8.5million grant from the US Air Force Office of Scientific Research.
The researchers will look at three ways to create entangled quantum memories for use in securing long distance transmission of secure information. The work will be led by Georgia Tech, with researchers from Columbia University, Harvard University, MIT, the University of Michigan, Stanford University and the University of Wisconsin.
"We want to develop a set of novel and powerful approaches to quantum networking," said Alex Kuzmich, a professor in Georgia Tech's School of Physics and project's principal investigator. "The three basic capabilities will be: storing quantum information for longer periods of time, on the order of seconds; converting the information to light; and transmitting the information over long distances. We aim to create large scale systems that use entanglement for quantum communication and potentially also quantum computing."
Three physical platforms will be explored. These include: neutral atom memories with electronically excited Rydberg level interactions; nitrogen vacancy defect centres in diamonds; and charged quantum dots.
"We aim to be able to combine systems, so that instead of just one memory entangled with one photon, perhaps we could have four of them," Prof Kuzmich added. "This may look like a straightforward thing to do, but this is not easy in the laboratory. The improvements must be made at every level, so the difficulty is significant."
Among the challenges ahead are maintaining separation between the different memory systems, and minimizing loss of light as signals propagate through the optical fiber systems that would be used to transmit entangled photons.
"The immediate focus is on communication, including memories and distributed systems, which is important for sharing and transmitting information," Prof Kuzmich concluded. "It also has implications for quantum computation because similar techniques are often used."