Wednesday, November 19, 2008

Rerun: Schrodinger's Cat

I have to run off to class and don't have time to write a proper entry so you get another science lesson. Tomorrow I tell you about the Dougmas Jar.

In 1935 Irwin Schrödinger came up with the thought experiment known as "Schrödinger's Cat".

In the previous lesson how we learned that subatomic particles, such as electrons, don't really seem to exist in one place until you see them. Instead they give the appearance of existing in a cloud of places where they possibly or probably are until they're observed.

Here's how Schrödinger suggested you imagine it in relation to isotope decay.

One can even set up quite ridiculous cases. A cat is penned up in a steel chamber, along with the following device (which must be secured against direct interference by the cat): in a Geiger counter there is a tiny bit of radioactive substance, so small, that perhaps in the course of the hour one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges and through a relay releases a hammer which shatters a small flask of hydrocyanic acid. If one has left this entire system to itself for an hour, one would say that the cat still lives if meanwhile no atom has decayed. The psi-function of the entire system would express this by having in it the living and dead cat (pardon the expression) mixed or smeared out in equal parts.

It is typical of these cases that an indeterminacy originally restricted to the atomic domain becomes transformed into macroscopic indeterminacy, which can then be resolved by direct observation. That prevents us from so naively accepting as valid a "blurred model" for representing reality. In itself it would not embody anything unclear or contradictory. There is a difference between a shaky or out-of-focus photograph and a snapshot of clouds and fog banks.

Huh? Let me rephrase.

Take a box. In the box you put a cat. Next to the cat you put a vial of poisonous gas. The vial of gas is sealed by a complicated device containing an atom of a radioactive element that has a 50/50 chance of decaying in the next hour. When that element decays it will release the gas and the cat will die. Now seal the box.

When you come back in an hour the radioactive element may or may not have decayed. In fact the math shows that it has both decayed and not decayed and it has neither decayed nor not decayed. The only way to find out if it has decayed or not is to open the box and look at the cat. Until the box is opened the state of the cat is in flux. The cat is both dead and alive and neither dead nor alive.

Irwin regretted writing this explanation for the rest of his life. Most people misunderstood what he's explaining. The cat isn't real. The experiment wouldn't work. It's only told to try to explain subatomic behaviors on a scale we can better grasp

Among physicists this thought experiment has provoked several philosophical physics questions. You can read more about them at Wikipedia. Among non-physicists this provokes mostly misunderstandings. In the crap-science film "What The #$*! Do We Know" they try to make this a point of religious thought for worshipers of a 35,000-year-old warrior named Ramtha.
Some eastern philosophies make the point that we control our own universe. This is true as far as how an individual views his own life. Getting fired can be a crushing blow or a breaking of chains. Your car breaking down can be a point of great stress or the beginning of a story you can tell for weeks. But your viewpoint can't change the nature of water or manipulate matter as the movie tries to claim Schrödinger proved.

1 comment:

wiseml6779 said...

we are looking at this from the out side. do the results change if we look from the inside? How could joe who is in the box be alive or dead or neather when he can say that he is alive. The way I see it all he was doing is trying to impress is buddies by finding a new way to ask if a tree falls in the forest.