All I want for Christmas is some cool new physics

Brenda Cooper @ 22-12-2010

I’m a bit of a physics geek.  Not that I can do the math.  But I’ve always wanted to know how the world works, and physics is the very coolest science for that.  The foundation.  So I decided to find three bits of news in physics to put forward as a little gift for my fellow science geeks – a bit of how the world might work for the holiday season. Continue reading “All I want for Christmas is some cool new physics”

Quantum coms?

Aliette de Bodard @ 11-09-2010

Apparently, China has managed to make quantum “teleportation” work, using a blue laser over a range of 16km–thus paving the way for extra-secure communication. Basically, they used entangled particles: every modification to the state of one is reflected instantly in the other.
Pretty darn cool. No idea how close to feasible we are (probably further off than the article implies), but that’s a neat application of quantum physics.

The security of using quantum teleportation to distribute cryptographic keys, on the other hand, is upheld by the laws of physics and has a seemingly infinite time horizon. These keys cannot currently be detected and cracked even with the help of the most powerful computers. Owing to the Heisenberg Uncertainty Principle, the quantum states of photons cannot be observed without changing the state of the particle, which has the result of immediately informing the sender and receiver of any eavesdropping. Quantum communication can thus be used to send the most sensitive information, including keys to decode encrypted data sent over less secure means.

(more on quantum cryptography here at Wikipedia, and here at pcrypto. The last is great, though it’s mostly research papers).

Aliette de Bodard is a Computer Engineer who lives and works in France. When not wrestling with Artificial Intelligence problems (aka teaching computers how to analyse what they see), she writes speculative fiction. She is the author of the Aztec fantasy Servant of the Underworld from Angry Robot, and has had short fiction published in Asimov’s, Interzone and the Year’s Best Science Fiction.

Quantum motor with just two atoms

Tom James @ 19-09-2009

Quantum-motorResearchers at the University of Augsburg in Germany have developed a blueprint for a kind of quantum electric motor that uses just two atoms:

Their motor consists of one neutral atom and one charged atom trapped in a ring-shaped optical lattice. The atoms jump from one site in the lattice to the next as they travel round the ring. Placing this ring in an alternating magnetic field creates the conditions necessary to keep the charged atom moving round the the ring.

As with many elements of quantum physics it is difficult to imagine precisely what you could do with such a miniscule motor, but for the time being the researchers are seeking to attach the motor to a nanonoscopic resonator, thus making the resonator vibrate.

In the meantime we are left speculating as to what peculiar corners of which unexpected futures devices such as this could find a use and a narrative.

[via Slashdot, from Technology Review][image from Technology Review]

Light in a bottle

Tom James @ 29-07-2009

microresonatorScientists have developed a technique for confining light within a bottle:

Similar to the motion of a charged particle stored in a magnetic bottle, i.e., a particular spatially varying magnetic field, the light oscillates back and forth along the fiber between two turning points. For this reason, this novel type of microresonator realized by the physicists in Mainz is referred to as a bottle resonator. Tuning the bottle resonator to a specific optical frequency can be accomplished by simply pulling both ends of the supporting glass fiber. The resulting mechanical tension changes the refractive index of the glass, so that depending on the tension, the round-trip of the light is lengthened or shortened.

This could lead to the creation of a glass fibre quantum interface between light and matter, which in turn is an important component of hypothetical quantum computers and quantum communication systems.

[from Physorg][image from Physorg]

Mono-molecular optical transistor brings quantum computing closer

Paul Raven @ 08-07-2009

Researchers at the Swiss Federal Institute of Technology have managed to make an optical transistor from a single molecule, offering another potential stay of execution for Moore’s Law.

ETH’s Martin Pototschnig told us more about the molecule used for the experiments. “It is a small hydrocarbon molecule called dibenzanthanthrene (DBATT). The molecules are doped in n-tetradecane, an organic solvent. So the sample is a pink liquid at room temperature. Then we cryogenically cool the small portion of the sample then the n-tetradecane freezes and forms a molecular crystal.”

The molecule itself is about 2 nanometers in size, over ten times smaller than standard transistors, which means that a lot more could be integrated in a single chip.

Great, you may be thinking, but what is it good for? Well, not much. Yet.

By using a laser beam to impose the quantum state of a molecular transistor, the research team demonstrated control of a second laser beam, which reflects the way in which a conventional transistor works.

“The next step is to ‘connect’ two or more [single-molecule optical transistors],” Pototschnig told us with regard to future areas the team will be focusing on. “In other words, we have to connect two molecules in a way that the quantum mechanical superposition state of each molecule is exchanged in a coherent manner. Only that way the strength of the quantum computing principles can be fully taken advantage of. We are in the middle of coming up with actual ways to implement the connection idea.”

Doesn’t really explain much, but then I don’t really fully understand how quantum computing is meant to work, despite numerous attempts to research it a bit further… if anyone can point me towards a good simplified explanation, please pipe up in the comments.

One thing I do know is that a lot of people are skeptical of quantum computing having any practical real-world applications, assuming it ever makes it out of the developmental stages. But then IBM’s chairman of 1943 never imagined the world would need more than five regular computers, and he’s been proved very wrong since then. Human ingenuity being what it is, we’ll find something to do with it once it’s here.

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