[extropy-chat] Technique detects entangled quantum states

[Giu1i0 Pri5c0]

>From Technology Review: 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.
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.
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 (Detection of
Entanglement with Polarized Photons: Experimental Realization of an
Entanglement Witness).
[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.]
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