Monday, November 12, 2007

Do Classical Laws Arise From Quantum Laws?

This is a timely subject, since the issue of "decoherence", and how far quantum laws can be extrapolated into our classical world seems to be the topic of discussion on here (see comments from the last few blog entries).

Physicists from Austria have formulated a theoretical scenario in which QM laws are the underlying physical description of the classical world that we see today.

“Our motivation is to understand how the classical world comes out of quantum physics,” Kofler says. “The established approach in research is decoherence where one has to take into account the complexity of systems and interactions with environment.” It is interaction with the environment that brings decoherence into play, destroying quantum coherences and making it impossible to observe quantum phenomena. “We believe we found a process complementary to decoherence which can explain the quantum-to-classical transition.”

The exact reference to the paper is as follows:

Johannes Kofler and ńĆaslav Brukner, "Classical World Arising out of Quantum Physics under the Restriction of Coarse-Grained Measurements", Phys. Rev. Lett. 99, 180403 (2007).

Again, many people who don't understand this think that QM phenomena can be easily extrapolated, and used in mystical ways to explain human behavior, our world, etc. They can't! QM phenomena are not easy to find. If it is, we would have seen it already and won't have to wait till about 100 years ago in human civilization to formulate it! And not only that, QM effects are difficult to maintain because a system can interact so easily with its environment, destroying the coherence that is necessary to preserve such quantum phenomena.

So stop it already!



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