Tuesday, August 27, 2013

Here, Kitty Kitty

Erwin Schrödinger, 1887-1961
Earlier in the month, August 12 to be exact, Google honored Erwin Schrödinger with a "doodle." I have to confess I’ve never been much of a physics enthusiast. When I read the name Schrödinger, I only think of one thing: a dead cat in a box. Or is it two dead cats? No, wait. One cat is dead, but the other is alive. No, it’s definitely one cat but it’s both…Well, at this point I’m just confused.

Erwin Schrödinger was born August 12, 1887, in Vienna. In modern parlance, he was home schooled until the age of 12 at which point his parents hired tutors. Although he excelled in mathematics and the sciences, he also showed a keen interest in poetry and the humanities. Perhaps this latter interest explains the …quirkier aspects of his most famous thought experiment. In the course of his career he worked on a variety of physics problems including general relativity and radiation theory, but he is considered the father of Wave Mechanics. Just as Einstein had his annus mirabilis, Schrödinger experienced a two miraculous months, December and January 1925-1926, in which he wrote the first of four earth-shaking papers on wave equations and mechanics. But Schrödinger didn’t imprison a cat, until 1935.

An existing theory proposed by a group called the Copenhagen School stated that a radioactive sample could be in a superpositional state, that is, both decayed and not decayed at the same time. Schrödinger found this implausible, if not ridiculous, and set out to create a thought experiment to disprove the Copenhagen School. In December of 1935 he wrote a paper with the following gedankenexperiment, or thought experiment. He imagined a box in which a scientist places a cat, a sealed vessel of cyanide gas, a radioactive isotope, and a radiation monitor with a hammer attached. There is a fifty percent chance the isotope will decay in one hour. If the monitor detects decay, the hammer will drop onto the vessel of cyanide, breaking it, releasing the gas, and killing the cat. If the isotope does not decay, the cat lives. If the superpositional theory was correct, until the box was opened the cat was both dead and alive.

According to some physicist, after considering his own thought experiment, he began to question his earlier conclusion. Perhaps the cat could be both alive and dead! After all, he reasoned, there is no way to objectively know without opening the box, but once you open the box there are no longer two possibilities. Thus was born the paradox, or wave function, known as Schrödinger’s cat.
In science circles, this thought experiment was like a modern Internet video that goes viral. The paradox spread and other scientists modified it, trying to break it mathematically or logically. Eugene Wigner even suggested placing a human in the box, but others pointed out that although the human might recognize his or her state there would be no empirical evidence for observers outside the box. The wave function would remain intact until you opened the box; the human could be both alive and dead. (Remember, this was just a thought experiment.)

Schrödinger’s cat has remained a standard of quantum mechanics since 1935 with physicists arguing both for and against. Subsequent quantum experiments in our own time seem to have provided proof that atoms at the quantum level are, in fact, unpredictable enough to be spinning both counter clockwise and clockwise. The wave continues to wash over us.

For a more scientific explanation of the cat in the box paradox try the following video:

For a more detailed, academic discussion watch this video:

And by the way, it was only a thought experiment. No cat, or cats, were harmed in the filming of these videos.

Submitted by David Ryan
Business, Science & Technology Department
Central Library

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