Saturday, April 16, 2016

The Revenge of Schrödinger's Cat


Quantum theory has produced an assortment of results that fly in the face of common sense.  Particles that can be waves, particles that can be in two places at once - or nowhere at all - our being unable to know where something is and also where it's going... even quantum theorists don't understand these ideas except mathematically - if even then.

 
In order to demonstrate one of the seeming paradoxes of quantum theory, Erwin Schrödinger proposed a thought experiment.  He imagined a box in which there was a cat, a bottle of poison, and a bit of radioactive material.  A device was set up to detect whether the material emitted any radiation.  If it did, the bottle of poison would be opened, and the cat would die.  If not, then the cat was spared.  The box was closed off and there was no way to know what happened inside until it was opened.

Schrödinger's conclusion was that since there was no way to know what happened inside the box before it was opened, the cat was in two states - both alive and dead. This experiment is often referred to as Schrödinger's Cat.

His thought experiment was an exaggeration of a simpler situation - where a single subatomic particle could have one of two (or more) possible states.  Some physicists considered that until the particle's state was examined, it had no state - or rather, was in all possible states at once.

I have several problems with this.  First, just because you don't know what's going on, doesn't mean the Universe is undecided.  It's a measure of your ignorance, not of how the Universe works.  It's all very philosophical and everything, but it's all bullshit.  Does the world behind me really cease to exist simply because I don't see it?

Second, WTF?  Why is it always cats that get put into these situations?  Why not Schrödinger's Puppy, or Schrödinger's Baby Seal?  No, it's always got to be a cat.

Anyway, guys like Schrödinger piddled around with their math, made up stuff about quanta and quantum entanglement and whatever else, and actually managed to make some serious progress in technology.

One of their more exciting discoveries - at least if you're into death rays - was the laser.  That never would have been discovered without solid quantum theory.  It's just too weird for classical physics.  But we've managed to produce bursts of concentrated, coherent, monochromatic light that doesn't spread as it travels.  A flashlight will spread out so that at a moderate distance it becomes very dim.  A laser holds together so you can see the spot a long way off.

And what use have we made of this scientific wonder?  Mostly we amuse our cats with laser pointers.  Throughout the world at this very moment, millions of cats are eagerly chasing red dots, probably wondering why their humans are laughing at them.

Screw you, Schrödinger.


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