|A veritable superposition!|
An amusing picture at Google this morning, marking Erwin Schrödinger's 126th birthday. The picture shows his eponymous cat in a superposition of alive and dead states. The cat-in-box wave function |ψ> shows the amplitude for each of these quantum states to be √(1/2).
|ψ> = (cat-alive + cat-dead)/√(2).We now know that due to environmental interactions known as decoherence the superposition of these two orthogonal quantum states decays almost instantaneously into either the cat-alive state or the cat-dead state. What is not known is how the world decides between these outcomes (although quantum mechanics allows us to work out the probabilities = the square of the quantum amplitudes: in this contrived example 50% for cat-alive and 50% for cat-dead).