Friday, December 22, 2017

Santa Claus and Schrödinger's Cat

One of the frequent arguments against the existence of Santa Claus is the question, "How could he possibly make it to every home throughout the whole world in one night?"

At last, quantum physics gives us the answer.

Many are familiar with the thought experiment known as "Schrödinger's cat," as well as Heisenberg's uncertainty principle and the so-called "observer effect." German theoretical physicist Werner Heisenberg demonstrated in 1927 that both the speed and position of an elementary particle could not be determined at the same time. Related to this was the observer effect, in which observation of a phenomenon necessarily changes that phenomenon. Based on these developments, the so-called Copenhagen interpretation of quantum phenomena was based on probability: one could not predict the position of a particular quantum particle at a particular time; the best one could do would be to predict the probability of it being in a certain region. Prior to being measured, the particle could not be said to be in any definite position; measuring where the particle is causes a phenomenon known as "wave function collapse," causing the particle to occupy a specific position.

In response to this interpretation, Austrian physicist Erwin Schrödinger devised his famous cat experiment in 1935. He imagined a closed and opaque box containing a cat (alive when placed in the box), a vial of gaseous poison, and a triggering mechanism which breaks open the vial when a single radioactive atom decays. The decay of an individual atom cannot be predicted--only the half-life, during which half of the atoms in a given sample will have decayed, can be known. For that reason, one cannot know exactly when the mechanism is triggered, and therefore when the gas is released, and therefore whether the cat is alive or dead. According to the Copenhagen interpretation, the cat in the box is both alive and dead simultaneously until someone opens the box to find out.

Until now, no one has thought to apply this logic to the behavior of Santa Claus on Christmas Eve.