Tuesday, March 19, 2019

Quantum Quanta!

     Einstein, referring to his skepticism about quantum mechanics, is said to have remarked "God does not play dice."

     Subsequent physics tells us that the dice are, indeed, rolled; and subsequent science journalism is something of a crapshoot, too.

     Sadly, the only probability in the latter is that the journalist, lacking subject-specific expertise and usually working against a deadline, will probably get something wrong.  If the subject is "quantum (whatever), that probability approaches certainty.

     It rarely matters.  Nobody's doing advanced physics using internet filler as a primary source, and the daily practical application you or I have for quantum (whatever) doesn't exist.  Sure, someday it may secure your electronic transactions or supercharge supercomputers, but it hasn't yet.

     Nor has it made time run backwards, but you couldn't've told that from the headlines when some research into the "arrow of time" got sort of quantum-interesting.  Those headlines led of counter-headlines explaining the experiment and its context, or trying to, H. G. Wells, Eloi and all.  And that led into deep and tricky water for one writer.

     He starts out talking about processes that run as well in reverse as forward and uses macro analogies, first an "ideal" model of the Earth orbiting the sun: "Look at that system going forward in time, and the Earth orbits in a clockwise direction. “Reverse” time and instead the Earth will travel in a counterclockwise orbit. Both are equally realistic."

      Yes, that's correct.

     "Or think of two billiard balls colliding. You can run the video in either direction and it still seems physically plausible."

      No! It's not even a good fake unless the pool table is frictionless and the billiard balls are mathematical ideals.

      Entropy is "time's arrow." We can fool our senses into ignoring it but in most physical examples, it's still there, though not always in ways we can see unassisted.

1 comment:

Douglas2 said...

Obligatory video link