A cat, a flask of poison and a radioactive source are placed in a sealed box. If an internal monitor detects radioactivity, the flask is shattered, releasing the poison, which kills the cat. The Copenhangen interpretation of quantum mechanics implies that after a while, the cat is simultaneously alive and dead, in a quantum superposition.
Other interpretation:
- many-worlds interpretation – both alive and dead states of the cat persist after the box is opened, are decoherent from each other.
Benc Tan 