Bristol University isn't the only one messing around with photons for quantum computing, the US Air Force is also trying to control the pesky devils for the greater good. This brainy bunch are looking at "freezing" the notoriously finicky tools needed to get photons to interact with each other as holograms.
For photons to be useful within a quantum computing setting, you need them to interact with each other. Problem is, photons don't like hooking up with anything else, let alone themselves. Makes you wonder why researchers are pursuing them with such vigor, but it's their purity of transmission that makes them the best possible vector for transferring information with a quantum computing setting. Hell, we already know that fibre optics are the best form of data cabling available just for our humble transistor-based computers, so photons seem a logical step for the high fidelity requirements of quantum computing.
So, to get photons to interact with each other boffins use an instrument called an interferometer, which superimposes the photons essentially forcing them to interact. The major issue facing researchers attempting to manipulate photons is that interferometers are incredibly sensitive and are extremely easy to throw out of alignment; breathe a tad too hard and you'll have to recalibrate the blighters.
Boffins from the US Air Force Research Laboratory think that by freezing the interferometers in
carbonite glass, thereby creating a hologram of said instrument, they'll avoid the need for constant recalibration and turn them into something useful.
There are two issues with this approach though: firstly, its fixed and non-reprogrammable, but that's OK, because there's a need for that kind of constant system; and secondly, bits of glass take up space, and that means that when you need to ramp up the parallel processing capacity of any potential quantum computer you're going to need a truckload of space.
Still, Jonathan McDonald and his team reckon they can use "off-the-shelf" holographic systems to create the fixed interferometers, which means the costs and the speed at which systems can be rolled out will be kept to a minimum.
It's good to have multiple approaches for sure, and I might be biased, but I'm still plunking my money down on the reprogrammable system the Brits are pushing. [Cornell via MIT Technology Review via Engadget]
Image credit: Holograms from Shutterstock