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In quantum mechanics, the consistent histories approach is intended to give a modern interpretation of quantum mechanics, generalising the conventional Copenhagen interpretation and providing a natural interpretation of quantum cosmology.〔F. Dowker and A. Kent, "Properties of Consistent Histories", Phys. Rev. Lett. 75, 3038 - 3041 (1995)〕 This interpretation of quantum mechanics is based on a consistency criterion that then allows probabilities to be assigned to various alternative histories of a system such that the probabilities for each history obey the rules of classical probability while being consistent with the Schrödinger equation. In contrast to some interpretations of quantum mechanics, particularly the Copenhagen interpretation, the framework does not include "wavefunction collapse" as a relevant description of any physical process, and emphasizes that measurement theory is not a fundamental ingredient of quantum mechanics. ==Histories== A ''homogeneous history'' (here labels different histories) is a sequence of Propositions specified at different moments of time (here labels the times). We write this as: and read it as "the proposition is true at time ''and then'' the proposition is true at time ''and then'' ". The times are strictly ordered and called the ''temporal support'' of the history. ''Inhomogeneous histories'' are multiple-time propositions which cannot be represented by a homogeneous history. An example is the logical OR of two homogeneous histories: . These propositions can correspond to any set of questions that include all possibilities. Examples might be the three propositions meaning "the electron went through the left slit", "the electron went through the right slit" and "the electron didn't go through either slit". One of the aims of the theory is to show that classical questions such as, "where are my keys?" are consistent. In this case one might use a large number of propositions each one specifying the location of the keys in some small region of space. Each single-time proposition can be represented by a projection operator acting on the system's Hilbert space (we use "hats" to denote operators). It is then useful to represent homogeneous histories by the time-ordered tensor product of their single-time projection operators. This is the history projection operator (HPO) formalism developed by Christopher Isham and naturally encodes the logical structure of the history propositions. The homogeneous history is represented by the projection operator This definition can be extended to define projection operators that represent inhomogeneous histories too. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「consistent histories」の詳細全文を読む スポンサード リンク
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