Herding Photons Through the Quantum Hall for Computers of the Future

Trying to get photons — particles of light used to carry data — from one place to another is, as the saying goes, “like herding cats.” Apparently, it’s easier to get them to agree on their destination when funneled through fiber optic cable — even if it’s over a distance of thousands of miles over the hill and through the woods (and under the ocean) — than to get the pesky buggers to jump a few simple nanometers away through a computer circuit. It’s like my friend Mark before he stopped drinking. He’d take a cab across town to swill down a few pints of whatever the bartender had on special instead of imbibing what he had at home in the privacy of his own refrigerator. Still, I guess it kept him from drinking alone…

Herding Photons Through the Quantum Hall for Computers of the FutureResearchers from the Joint Quantum Institute of the National Institute of Standards and Technology (NIST) and the University of Maryland, with Harvard University joining into the fray have decided to take up the challenge and find out how photons can be enslaved manipulated to be more agreeable to human purposes. The initial goal was to guide photons in a way that would make information processors in computers (not just the ones in giant research labs, but the ones we’ve got on our desks and laps) more efficient with photon delay devices and an alternate-pathway technique to bypass the problems inherent in their design. An interesting side effect of the research, however, is that it may allow for better observation of the elusive quantum Hall effect in which electrons interfere with themselves while traveling through a magnetic field. Overcoming the problems of the quantum Hall effect is a much mightier goal than what the researchers were hoping for; it’s a bit like finding out that watching someone make an intimate dinner for two will give you the insight to solve world hunger and power cars on the resultant warm, fuzzy feelings.

Jacob Taylor of NIST and the JQI says: “We run into problems when trying to use photons in microcircuits because of slight defects in the materials chips are made from. Defects crop up a lot, and they deflect photons in ways that mess up the signal.”

JOI’s research lead Mohammad Hafezi chimes in: “The photons in these devices exhibit the same type of interference as electrons subjected to the quantum Hall effect. We hope these devices will allow us to sidestep some of the problems with observing the physics directly, instead allowing us to explore them by analogy.”