Saturday, March 12, 2016

Quantum physics for the rest of us

The question I submitted to Ethan Siegel at Starts With a Bang!:

Dear Ethan,

I have more than one question, and it seems logical to package them into one note rather than to separate them into separate notes. But if that's against the law, I apologize.

1) I'm pretty skeptical about things, but fortunately I'm more skeptical regarding, say, faith healing than I am regarding quantum physics. However, when I read about the spooky action at a distance, the single particle going through one slot and causing waves to appear in another slot as if the particle had gone through both slots regardless of the distance between them, I can't help thinking "Oh right, they know they're emitting one particle at a time." I imagine the way they verify that a single particle is emitted is with a chain of technologies, with the more sophisticated technologies built on the results of the simpler, unless physicists have really, really good eyesight. I know that the results of this type of experiment are repeatable and that there's been extensive research into this phenomenon to try to understand quantum entanglement, but still. A single particle? Also, if I remember right, the particle can go through either slot, and I don't understand how that's possible. Is the emitter aimed between the slots or at one slot? Also, if there are more than two slots, do all of the slots exhibit the same phenomenon, or just one? And finally, isn't it possible that the phenomenon is produced by the slot itself? Like soundwaves bouncing around within a niche in a wall and producing a different wave pattern than would otherwise be produced by the soundwaves reacting to a plain wall. A weak analogy, yes, but it's the best I can do.

2) From what I know about quantum physics, which isn't much, the various models of, say, string theory are represented by whiteboards filled with equations that the average person finds incomprehensible. Whenever I encounter that, I can't help thinking "Can they write that out in longhand?" I don't know, it seems that the natural-language version of a model is as important as the mathematical version. The way we understand the universe is through language; we generally name things rather than assigning them numbers. I know that translating all of the symbols in a model, all the way down to the arithmetic operators, into natural language would produce text that would probably be book-length. But still, every mark on the whiteboard has a corresponding meaning in natural language. If a physicist doesn't want to translate the mathematical model into text, that would seem to be no more than his wanting to maintain the archetypal boy's club with its secret decoder rings and "No girls allowed" sign. How much is exclusivity for the sake of exclusivity prevalent in the profession? And then there's the quote about being able to explain something so a barmaid can understand it or one doesn't understand it well enough himself. So, can they write it out in longhand; if so, do they; if not, will they? We would really appreciate it. Some of us don't have enough life left to start at physics 101 and work all the way up to quantum mechanics.

John Garvey

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