Sunday, July 22, 2012

Mixed science news

'' Could Tractor Beams Be Made From Light? ... The idea behind Segev’s “tractor beams” goes something like this. In these materials, while the individual photons are refracted in one direction, the overall shape of the light waves will be refracted in the opposite direction. This means that the wave’s group and phase velocities move in different directions — that is, the overall shape of the wave moves in one direction (carrying the wave’s electromagnetic energy with it), while the individual groups of photons move in the opposite direction.

Since the two forces are moving in opposite directions, this creates a theoretical area of negative radiation pressure in the middle. Controlling the direction of the negative pressure could make particles caught in the middle move.
Usually this would be an effect without practical consequence because existing metamaterials are metallic, and thus absorb electromagnetic radiation. Segev’s paper proposes instead using natural crystals like quartz which possess the property of “birefringence” — that is, they have several refraction indices.'' [source]

'' ‘Schrödinger’s Hat’ Uses Invisibility to Measure Quantum World ...
Conceptually, a Schrödinger’s hat is like an invisible battery. It captures a tiny bit of energy without fiddling with the [energy] waves so you can later get a measurement. ...
If you’re trying to image something at the nanoscale, say a computer chip or nanodevice, you might get very close to it without disturbing it.  '' [source]

'' Invisibility Cloak Uses Mirages to Make Objects Vanish'' [video]

'' First, Invisibility Cloaks; Now, Real-World Levitation ...
From the branch of science that gave us the real-world invisibility cloak comes… honest-to-God levitation. In theory, at least.'' [source]

'' Researchers break record, keep quantum computing qubit alive for 3 minutes ...
The trick used at the University of Oxford has to do with coaxing the computational particles into superposition and keeping them there in two different spin states simultaneously. Researchers used a form of extremely pure silicon-28 (which is non-magnetic and non-reactive) as the medium for the test. A number of phosphorus atoms were suspended in the silicon, and scientists found that the particles behaved as if they were in a vacuum.'' [source]

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