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Wednesday, April 11, 2012

A Roundup of Science News

Scientists don’t know much about the cause of Kawasaki disease—a disease of blood vessel inflammation most commonly found in Japan—but they do know one thing: Japanese outbreaks are highly correlated with winds from central Asia. When those same winds blow thousands of miles across the Pacific to Hawaii and California, Kawasaki disease ends up there too. The disease affects generally children under the age of five. Blood vessels through the body become inflamed, leading to rashes, a characteristic “strawberry tongue,” and death in some untreated cases.

The fastest random number generator is based on vacuum noise (i.e. , the appearance and disappearance of sub-atomic particles in a vacuum):
Most existing random number generators work off of some kind of computer algorithms. Those algorithms are pretty good, but if you know the inputs you can figure the outputs. In other words, the numbers aren’t truly random, they are just correlated in a way that is unknown to the user. But Vacuum noise is truly random--quantum theory ensures the numbers are truly unpredictable. By measuring the noise in a vacuum, the team can generate billions of random numbers per second. The only thing limiting them in their ability to flood the world with random numbers is the capacity of their Web connection.

But that doesn’t mean you can’t get your very own sequence of unique random numbers off the Web. Access ANU’s randomness generator here.
Finally, researchers have built an elementary quantum network.
It consists of two coupled single-atom nodes that communicate quantum information via the coherent exchange of single photons. “This approach to quantum networking is particularly promising because it provides a clear perspective for scalability”, Professor Rempe points out.

Quantum information is extremely fragile and cannot be cloned. In order to prevent alteration or even the loss of the information, it is necessary to have perfect control over all quantum network components. The smallest stationary memory for quantum information is a single atom, and single photons represent the perfect messengers. Efficient information transfer between an atom and a photon, however, requires strong interaction between the two, which cannot be achieved with atoms in free space. Following a proposal from Professor Ignacio Cirac (director at the MPQ and head of the Theory division), the group of Professor Rempe has invested many years working on systems in which single atoms are embedded in optical cavities. These cavities are composed of two highly reflecting mirrors placed at a very short distance. The emission of photons from an atom inside a cavity is directed and can therefore be sent to other network nodes in a controlled way. A photon entering the cavity is reflected between the mirrors several thousand times. In this way, the atom-photon interaction is strongly enhanced, and the atom can absorb the photon coherently and with high efficiency.

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