USA, April 2007 (Ars Technica): [HPI note: we recently found this article which, though a few years old, is a good explanation of the almost mystical discoveries some physicists find today.]
It may be one of the best-kept secrets in science: we really don’t have a good grip on reality. Two of the best models of physical reality, relativity and quantum mechanics, appear to be fundamentally incompatible. That point is reinforced by an article and a perspective from Nature magazine. The articles describe results that show that quantum mechanics describes the behavior of a system called “local realism.”
Local realism can be understood fairly easily: the properties of particles can be completely described, and those properties remain localized, meaning that properties can’t be transmitted to a different location faster than the speed of light. That can be translated as: “Things are the way things are, right here.”
But if take into account a process known as entanglement, in which particles immediately behave according to other entangled particles which may be half a universe away, you have a problem. The “local reality” is either not local or, well, not real.
Many physicists haven’t been happy about this situation (including Einstein), and some have tried to compensate by creating what are termed “hidden variable” models, in which there are properties of reality that we don’t know how to measure.
That’s where the new paper comes in. A set of plausible models allowed us to test the way the infinitesimal particles that form our universe really behave. The results confirms odd quantum mechanics phenomena such as entanglement and discard the idea of a local reality.
Does this mean that it’s time to give up on reality? The authors sure seem to think so, wrapping the paper up with the statement that “We believe that our results … must abandon certain features of realistic descriptions.”
(For a complete and more arcane article, see the source above).