Schrodinger's+Cat

Interpretations of Quantum Physics

Schrodinger's Cat is a thought experiment that operates under the many worlds (also known as parallel universes) interpretation. This experiment was devised by Austrian theoretical physicist Erwin Schrodinger (1887 - 1961).

"Schrodinger's experiment involves a sealed box (allowing no outside interference) that contains a cat and a closed canister of poisonous gas. Attached to the gas canister is a mechanism containing a radioactive nucleus. When the nucleus decays, it emits a particle that triggers a mechanism which opens the canister, thereby killing the cat.

Since the nucleus, as long as it remains unobserved, is in a superposition of the "decayed" and "not decayed" states, then it logically follows that the cat must also be in a superposition of "alive" and "dead" states -- until the moment when the box is opened and its contents are observed by the scientist performing the experiment. The idea that the cat's fate is decided only when the box is opened seems to defy common sense -- so Schrödinger argued there must be some rules defining when the system "collapses" into one of the two states, and that this does not happen simply when the system is "observed"." ([])

When the box is closed the cat remains a wave of probability, meaning it is both dead and alive. Opening the box shatters this wave of probability, meaning that the cat will be one or the other.