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Spintronics: A New Way To Store Digital Data
by Joe Palca
December 17, 2010
npr.org 
Enlarge HYNIX/AFP/Getty Images
Semiconductor computer chips like this one rely on electricity — positive or negative charges — to store data. Using high power magnets in a lab, researchers have developed a new way to store data in the spin of an atom's nucleus.
HYNIX/AFP/Getty Images
Semiconductor computer chips like this one rely on electricity — positive or negative charges — to store data. Using high power magnets in a lab, researchers have developed a new way to store data in the spin of an atom's nucleus.
text size A A A December 17, 2010
Scientists at the University of Utah have taken an important step toward the day when digital information can be stored in the spin of an atom's nucleus, rather than as an electrical charge in a semiconductor.
The scientists' setup requires powerful magnets and can only be operated at minus 454 degrees Fahrenheit, so don't expect to see spin memory on the shelf at a computer store anytime soon.
Christoph Boehme, an associate professor at the University of Utah, says the most important thing he and his team have done is show that it's possible to store information in spin and read it rather easily.
Here's how they did it: First, they used a strong magnetic field to make sure all their atoms were pointing in the same direction. Then they measured which way the nucleus of an atom was spinning. Physicists don't talk about spinning clockwise or counterclockwise — they call the spins either up or down.
"This up and down can now represent information," says Boehme. "An up means a one, and a down means a zero."
Storing and manipulating these zeroes and ones — bits, in computer parlance — is at the heart of how computers work. Today, those zeroes and ones are stored using electric charge — positive or negative. In the future, things might be different.
"Instead of electronics, people want to use spins and build spintronics, and if you do so, you need to be able to store information," says Boehme.
'Multiple Universes'
As they report in the journal Science, they were able to store information in spins for nearly two minutes. But that wasn't the key achievement.
"The main focus of our study was to show you could read it with an electronic device," he says. In other words, they could use conventional electronics to read out the stored memory. Spintronics has some advantages over electronics. In theory, spin memory should be faster and take less energy to run than electronic memory.
Now, Boehme is working with conventional bits of information. But because he's working with atoms, the setup can take you into the mind-bending world of quantum information. Quantum physics is all about how atoms work.
"In quantum information, I can have a bit which is zero and one at the same time," says John Morton, a physicist at the University of Oxford in England. This idea of being in two places at once is hard to explain. Morton says one way to think about it is to imagine there are multiple universes out there.
"Whenever quantum mechanics allows something to exist in two states at the same time, the universe splits," says Morton, "and you have a universe where it's one thing and a universe where it's in the other state. You can along those lines think about a quantum computer as many parallel computers running in different universes."
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And as long as you can get those universes to talk with another, then you have a very, very powerful computer.
The Magic Of Quantum Computing
Now, don't feel bad if you're not quite getting why quantum computing is such a desirable thing to have.
"It's not an easy one to explain," says Stephen Lyon, a professor of electrical engineering at Princeton University. He and his colleagues are always trying to entice undergraduates to go into the field of quantum computing.
"The approach we've been taking is to say, if you think of a number between one and four, with a quantum computer you could know the number every time with only a single guess. That doesn't at all tell you how it works, but it does tell you that there's something in there that's kind of different from what most people are used to," says Lyon."It's kind of magical."
Of course it's not really magical — it's physics. Weird physics, but physics. |
