A team led by Alexander Lvovsky at the Russian Quantum Center (in Moscow), sought to replicate the Schrodinger’s cat experiment on a larger scale (and more faithfully to the original concept) using a semi-transparent mirror to put a single photon (the quantum particle of light) into a superposed state (one in which the photon passes through the mirror, the other in which it is reflected). Once this mixed state was achieved, they were able to “entangle” the two photons such that the behavior of one photo state was linked to the other. Then, in a clever bit of technological manipulation involving high-speed lasers, one of the quantum states was amplified so that it was imposed on hundreds of millions of photons (a mass of photons easily visible to the unaided eye, in theory, although the team used a non-visible wavelength of light). Following this, they returned the amplified light to its original one-photon (superposed) state. Upon measurement, they were able to confirm that the entangled state had been preserve throughout the duration of the experiment even while one of the quantum states had been imposed on a macroscopic system (the array of hundreds of millions of photons) for a period of time. A similar result was achieved at the thousand photon scale by Nicolas Gisin and colleagues at the University of Geneva in Switzerland using a slightly different experimental set-up. The physicists assert that their experiments represent the first time quantum entanglement has been achieved between a quantum (micro scale) object and a macroscopic object. “Our breakthrough has been that, so far, people have been able to build these superposition states containing only a few photons, and we’ve been able to do it with 160 million photons,” says Lvovsky.[source: see link, below] And while the large-scale object here is not quite at the level of an actual cat (and that would be cruel to the cat, in any event), according to MIT physicist Seth Lloyd (quoted in the recent New Scientist article): “It’s not the entanglement of something as big as a cat, but it’s at least a kitten.” Results of the two experiments were presented at the Second International Conference on Quantum Technologies, in Moscow, Russia, on July 23. Journal references: Nature Physics (Lvovsky et al) ‘Observation of micro–macro entanglement of light’ ; Nature Physics (Gisin et al) ‘Displacement of entanglement back and forth between the micro and macro domains’ Some source material (including quotes) for this post came from the New Scientist article: ‘Schrödinger’s ‘kittens’ made in the lab from photons’ by Katia Moskvitch, Read more at planetsave/2013/07/26/schrodingers-kittens-large-scale-quantum-entanglement-achieved-by-two-physics-labs/#lrOT5DK26fIwIiA8.99
Posted on: Mon, 29 Jul 2013 00:13:35 +0000
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