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<DIV>From <A
href="http://www.technologyreview.com/articles/rnb_012804.asp?trk=rnb">Technology
Review</A>: The laws of physics make things that are very small - like atomic
particles - act differently than objects in the larger world where we reside.
One weird quantum property is entanglement, which allows properties of particles
like atoms, photons and electrons to remain linked, or synchronized, regardless
of the physical distance between the particles. Entanglement is also very
sensitive to disturbances and therefore difficult to measure. <BR>Entanglement
figures prominently in efforts to build quantum computers, which use properties
of particles to compute. Quantum computers promise to be fantastically fast at
certain types of large problems, including those that would render today's
cryptography useless. Entanglement also figures in quantum cryptography schemes
that offer theoretically perfect security. <BR>Researchers from the University
of Rome in Italy have pushed the schemes forward by demonstrating a method for
detecting entanglement. The method could be used practically in five to ten
years, according to the researchers. The work appeared on Physical Review
Letters (<A
href="http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000091000022227901000001&idtype=cvips&gifs=Yes">Detection
of Entanglement with Polarized Photons: Experimental Realization of an
Entanglement Witness</A>). <BR>[Note: besides its relevance in quantum computing
technology, entanglement is important for our understanding of the structure of
reality as a fundamental level and can be used to distinguish experimentally
between different formulations of quantum physics.]</DIV></BODY></HTML>