Continuing with the tradition of celebrating scientists birthdays, Google has marked Erwin Schrödinger’s anniversary with a Schrödinger Cat doodle.
Erwing Schrödinger was born on August 12th, 1887 in Vienna, Austria. He developed fundamental results in early quantum theory providing the basis to the so-called wave mechanics, formulating the eponymous equation at the heart of quantum mechanics. His famous cat paradox came up as a way to highlight contradictions with common sense brought up by the interpretation of quantum mechanics.
The Schrödinger cat is a gedanken experiment applied to macroscopic systems which draws our attention to discrepancies generated by the Copenhagen interpretation. Imagine that we put a cat into a sealed container together with a contraption that has a lethal poison which can be released if a radioactive substance in the device undergoes radioactive decay. If a single atoms decays, an alpha particle is detected and the poison is released, therefore killing the cat. The question is thus, before opening the box, can the observer tell whether the cat is alive or dead? Since the fate of the cat is tied to the quantum mechanical wave function of the atom then the question can be answered by knowing the state of the latter. Nonetheless, according to quantum mechanics the atom is in a superposition of decayed and undecayed states which would mean that the cat is itself in a superposition of dead and alive states! When the observer finally opens the container, the cat is “observed” and thus the wave function is “collapsed” into one of the two states.