In a paper far too daunting for a Monday, researchers at the Air
Force Research Lab (AFRL) have described a novel way to build a simple
quantum computer. The idea: rather than using a bunch of finicky
interferometers in series to measure the inputs and outputs of data
encoded in photons, they want to freeze their interferometers in glass using holograms, making their properties more stable.
Quantum Computing with Holograms Just like that
Warner A. Miller, Grigoriy Kreymerman, Christopher Tison, Paul M. Alsing, Jonathan R. McDonald
Quantum computing requires encoding information into a quantum
medium, and light is the most obvious choice. Photons don’t have mass
and therefore don’t interact much with external forces; things like
electrical interference or magnetic fields don’t mess with the quantum
state, and photons travel straight through transparent matter (like
fiber optic cable or ambient air). But light is also a bit tricky
because photons don’t interact with each other well either. Processing
information in a photon at the receiving end can be particularly
problematic. To make quantum computing work, researchers generally use
interferometers, which basically make photons interact in a way that is
diagnostic of the state of the photons. That’s a roundabout way of
saying, interferometers enable quantum computations by basically being
the read and write devices for photons, with the output of one
interferometer feeding the input for the next.
But interferometers aren’t easy to work with. They lose their
calibration easily, so stringing together a series of interferometers to
conduct more complex calculations isn’t easy to do. So the AFRL team
had an idea: why not freeze the properties of the interferometers in
place by translating them to holograms “frozen” in a piece of tempered
glass. That way researchers could stack the holograms to perform simple
quantum functions without worrying about them losing their properties.
There’s an off-the-shelf commercial product called OptiGrate that is
apparently pretty ideal for this kind of holographic freezing.
Of course, there are drawbacks. For one, OptiGrate is one-time
write-only, so there’s no reprogramming a quantum setup once the
holograms have been frozen in place. They also aren’t scalable, at least
for the time being. Simple computations would be all they are capable
of.
Even so, there’s a need for reliable quantum computing schemes, even
very simple ones, and as yet there’s not real technology that’s stepped
into that space, Technology Review
tells us. So while this kind of thing is pretty nascent, it could be
the beginning of something bigger and better as technologies (like
OptiGrate) mature.
From popsci
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