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.