# What is meant by the collapse of the wave function?

Collapse of the wave function is part of some interpretations of quantum mechanics. Most notably, it this concept is used by the Copenhaegen interpretation of quantum mechanics. Though the Copenhaegen interpretation is the most popular interpretation of QM, it is by no means the only one. All interpretations of QM agree that that the math behind QM is right, or at least right in certain limits. n Bohmian interpretations, for example, the wave function does not collapse. In the Copenhagen interpretation, a particle’s wave function is thought to exist in a large superposition of states until the moment of observation, and then it spontaneously collapses to a single state. Schroedinger mocked the idea of the wave function collapse by employing his famous live/dead cat analogy. If we have a box, that may have a live cat or a dead cat, and the life of the cat is clearly tied to a quantum mechanical observable, then under the Copenhagen interpretation, the cat is a superposition of dead and