Title: Schrödinger's cat - Wikipedia
Headings: Schrödinger's cat
Schrödinger's cat
Contents
Origin and motivation
Thought experiment
Interpretations of the experiment
Copenhagen interpretation
Many-worlds interpretation and consistent histories
Ensemble interpretation
Relational interpretation
Transactional interpretation
Zeno effects
Objective collapse theories
Applications and tests
Extensions
See also
References
Further reading
External links

Content: Copenhagen interpretation
A commonly held interpretation of quantum mechanics is the Copenhagen interpretation. In the Copenhagen interpretation, a system stops being a superposition of states and becomes either one or the other when an observation takes place. This thought experiment makes apparent the fact that the nature of measurement, or observation, is not well-defined in this interpretation. The experiment can be interpreted to mean that while the box is closed, the system simultaneously exists in a superposition of the states "decayed nucleus/dead cat" and "undecayed nucleus/living cat", and that only when the box is opened and an observation performed does the wave function collapse into one of the two states. One of the main scientists associated with the Copenhagen interpretation, Niels Bohr, offered an interpretation that is independent of a subjective observer-induced collapse of the wave function, or of measurement; instead, an "irreversible" or effectively irreversible process causes the decay of quantum coherence which imparts the classical behavior of "observation" or "measurement". Thus, Schrödinger's cat would be either dead or alive long before the box is opened by a conscious observer. Analysis of an actual experiment found that measurement alone (for example by a Geiger counter) is sufficient to collapse a quantum wave function before there is any conscious observation of the measurement, although the validity of their design is disputed. Many-worlds interpretation and consistent histories
The quantum-mechanical "Schrödinger's cat" paradox according to the many-worlds interpretation. In this interpretation, every event is a branch point.