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Phoenix666 [soylentnews.org] writes:

A team of quantum physicists at Aalto University led by Dr. Sorin Paraoanu managed to tame a so-called "dark state," [sciencedaily.com] created in a superconducting qubit. A superconducting qubit is an artificial atom fabricated on a silicon chip as an electrical circuit made of capacitors and tunnel junctions.

This technology is one of the most promising for the realization of quantum computers.

In the experiment, the circuit was operated in a regime where it no longer absorbs or emits electromagnetic waves of certain frequency, as if it would be hiding under an invisibility cloak -- hence the term "dark state." Then, by using a sequence of carefully-crafted microwave pulses, the team employed the dark state to realize a transfer of population from the ground energy level to the second energy level, without populating the first energy level. The amount of energy transferred in this process corresponds to a single microwave photon with about the same frequency as those in mobile phones or microwave ovens. This is verified by quantum tomography -- a technique of reconstructing the wave function (in general the density matrix) by applying rotations in an abstract qubit space followed by measurements.
...
Besides the relevance for quantum computing, the result also has deep conceptual implications. Much of our understanding of the reality is based on the so-called continuity principle: the idea that influences propagate from here to there by going through all the places in-between. Real objects don't just appear somewhere from nothing. But the experiment seems to defy this. Like in a great show of magic, quantum physics allows things to materialize here and there, apparently out of nowhere.

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