Saturday, July 05, 2014

Quantum Paradigm Shifts

Scot McKnight drew attention to some fun waves in the field of quantum mechanics. Since I've been working through George Gamow's version of the early events, and some other books as well, this is a very timely article.

If this new approach is true, here is how the history of science will read. In the late 1920s, when the key discoveries of quantum mechanics were being formed, there were two basic perspectives in play. On the one side was Niels Bohr, a dominating personality who stood at the center of the burgeoning developments.

1. Bohr had somewhat of a cult following among the younger physicists. He brought them to Copenhagen and provided not only the most stimulating thinking on offer in physics but a thriving social setting as well. He offered the probabilistic interpretation of what was happening on the nuclear level.

The probabilistic interpretation is fun. For example, in this approach, the prevailing approach, an electron doesn't have a defined trajectory. It's as if it exists in a kind of indeterminate, undefined state. If you interact with it--say you try to define its position--you are the one calling it out of its indeterminate state. You may find a position but you have, in a sense, created it by trying to measure it.

2. But there were others in the mix who, in the crucial year 1927, resisted this interpretation. The exchanges between Einstein and Bohr are the stuff of legend. Einstein was a loner. He was the apple of the public's eye but Bohr was the attraction among actual physicists.

Einstein's refusal to go along with the trend is notorious and he is usually seen as a loser in his later years. When I teach about scientific revolutions in philosophy class, I've always used Einstein as an example of normal science resisting new paradigms. I always end with the line, "but Einstein's dead now and can't object." The point is that social factors often play a significant role in what becomes the prevailing scientific theory of the day.

But if this new approach is correct, then Einstein proves to be more correct than Bohr, who also is long gone and unable to object. He's not throwing any more physics parties in Copenhagen any more.

The center of attention in this discussion is de Broglie, who ironically started us down, inadvertantly, the path toward the probabilistic interpretation. He was the one who inspired Schrodinger's wave equation, which is the basis for the probabilistic interpretation. Einstein, Schrodinger, Dirac, they all did not fully accept the Copenhagen interpretation. But they lost the argument... at least till now.

3. The tremors in the force are coming from fluid mechanics. de Broglie originally suggested that "pilot waves" accompanied nuclear particles. In that sense, the fundamental constituents of matter were both particles and waves. This is slightly different from the Copenhagen interpretation, which sees matter, in a sense, as neither until we interact with it.

This article suggests that Richard Feymann, the most charismatic figure in the physics of the mid-twentieth century, may have been fundamentally wrong about his characteristically Copenhagenish interpretation of the double slit experiment. There seems to be a cosmic justice in that. I know he was a funny guy, but probably a little too cocky for his own britches. I feel the same way about Hawking, and I was delighted to see him bite the dust over the Higgs boson.

It will be interesting to see where, if anywhere, this whole line of interpretation goes. If there is a critical turn, we could see a ten year period in the near future that is almost as exciting as physics was in the late 1920s.

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