The actual article is published in Science, which I think means there's a moratorium (of a few months?) on releasing the full text. That's apparently why the article's not available on the ArXiv.<p>The article is here: <a href="http://www.sciencemag.org/content/334/6060/1253.abstract" rel="nofollow">http://www.sciencemag.org/content/334/6060/1253.abstract</a><p>Entangling Macroscopic Diamonds at Room Temperature<p>K. C. Lee, M. R. Sprague, B. J. Sussman, J. Nunn, N. K. Langford, X.-M. Jin, T. Champion, P. Michelberger, K. F. Reim, D. England, D. Jaksch, and I. A. Walmsley<p>ABSTRACT: Quantum entanglement in the motion of macroscopic solid bodies has implications both for quantum technologies and foundational studies of the boundary between the quantum and classical worlds. Entanglement is usually fragile in room-temperature solids, owing to strong interactions both internally and with the noisy environment. We generated motional entanglement between vibrational states of two spatially separated, millimeter-sized diamonds at room temperature. By measuring strong nonclassical correlations between Raman-scattered photons, we showed that the quantum state of the diamonds has positive concurrence with 98% probability. Our results show that entanglement can persist in the classical context of moving macroscopic solids in ambient conditions.
Fwiw, this appears to be a reblog of: <a href="http://www.livescience.com/17264-quantum-entanglement-macroscopic-diamonds.html" rel="nofollow">http://www.livescience.com/17264-quantum-entanglement-macros...</a><p>which was previously submitted here: <a href="http://news.ycombinator.com/item?id=3302904" rel="nofollow">http://news.ycombinator.com/item?id=3302904</a><p>and also covered in the New Scientist: <a href="http://www.newscientist.com/article/dn21235-entangled-diamonds-blur-quantumclassical-divide.html" rel="nofollow">http://www.newscientist.com/article/dn21235-entangled-diamon...</a>
Question: Since we know that quantum entanglement does not provide for FTL communication, then what _are_ some practical uses for it? Why does it continue to get so much attention in research? This answer might be, "to learn more about quantum mechanics," but my impression is that entanglement is fairly well-understood in physics.
IANAP and the article is lacking on details where I most want them, but how does this show that the diamonds themselves are entangled, and not just the split light beam (à la the double-slit experiment)?