Wave function collapse

Collapse of the wave function or state reduction is a term of the Copenhagen interpretation of quantum mechanics. In quantum mechanics, a physical system is described by a superposition ( " superposition " ) of different states. In the Bra- Ket notation reads this

The total state is a superposition of all possible eigenstates each with weight. If a measurement is performed on such a system, the experimenters will always identify a single measured value (intrinsic value of a eigenstate ). Formally, this means that the superposition of states is reduced and projected by the measurement to a single state. The measured system is characterized by the measurement in exactly the measured state. This transition from the state of the superposition in a uniquely determined condition is referred to as state reduction. Since the initial state is represented as a state of Schrödinger'schen wave function, saith the Copenhagen interpretation also on the " collapse of the wave function".

History

First approaches to the explanation submitted by Werner Heisenberg and were formulated by John von Neumann in 1932 in his book Mathematical foundations of quantum mechanics postulates. The postulate of a instantaten collapse of the wave function calls since its launch forth contradiction. A popular thought experiment by Erwin Schrödinger

Should pursue the idea of an observer - dependent collapse of the wave function absurdity.

Other interpretations of quantum mechanics, such as the de Broglie -Bohm theory and the many-worlds interpretation come from without this concept. However, the many-worlds interpretation must introduce a host of measurement technically unreachable "worlds" in order to avoid the collapse of the wave function. The prevalent in recent decades interpretation is that the collapse does not have to be postulated, but there is an approximation, if one considers the inevitable coupling of the system with the environment, see decoherence.

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