Bulky test equipment used to perfect optical technologies for quantum communications will have to be miniaturized to the chip scale before commercialization.
Analysts predict that more that 51 percent of Internet traffic in 2012 will be generated by malware. Hackers frequently use the malicious software to intercept communications and beam data back to criminal websites. Quantum communications, on the other hand, could turn the tide against the bad guys by enabling uncrackable communications over the existing fiber optic connections used to connect major Internet hubs worldwide.
To develop this type of secure system, the U.S. Air Force Office of Scientific Research (AFOSR) recently funded a five-year, $8.5 million effort by seven U.S. universities to perfect quantum communications and the necessary short-term quantum memories needed to buffer quantum information while it is being transmitted. The universities participating in the five-year Multidisciplinary University Research Initiative (MURI) led by Georgia Tech include Columbia University, Harvard University, the Massachusetts Institute of Technology, the University of Michigan, Stanford University and the University of Wisconsin.
The basic technique being explored uses what is called quantum entanglement--the ability to synchronize encoded values over vast distances without the possibility of eavesdropping. By entangling photons that will shipped across fiber optic networks--what's called quantum encryption--the recipients can read the data without the possibility of it being intercepted by others.
"Our immediate focus will be on communications, including memories and distributed systems that integrate [quantum communications] with existing infrastructure--the optical fibers that are already deployed," said Georgia Tech professor Alex Kuzmich, MURI’s principal investigator. "We aim to create large-scale systems that use entanglement for quantum communication and potentially also quantum computing. [And] if we are successful over the next five years, long-distance quantum communications may become promising for real-world implementation."
MURI will explore three different approaches for creating entangled quantum memories with matter-light interactions, namely neutral atom memories with electronically-excited interactions, nitrogen-vacancy semiconductor defects engineered into on-chip diamond films, and by using charged quantum dots smaller that the wavelength of the light being communicated.
By studying how to store quantum information, convert it into light, and transmit it over long distance, the MURI program aims for four major goals: performance comparisons between the three methods of entanglement outlined above, extended entanglement lifetimes over several seconds (compared to the longest lifetimes today of 200 milliseconds), implement identical quantum states in dual memory nodes for easy error corrections, and downsizing of the necessary optical components to make the commercially feasible.