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In physics, a bispinor is an object with four complex components which transform in a specific way under Lorentz transformations: specifically, a bispinor is an element of a 4-dimensional complex vector space considered as a (½,0)⊕(0,½) representation of the Lorentz group.〔Caban and Rembielinski 2005, p. 2.〕 Bispinors are, for example, used to describe relativistic spin-½ wave functions. In the Weyl basis, a bispinor : consists of two (two-component) Weyl spinors and which transform, correspondingly, under (½,0) and (0,½) representations of the group (the Lorentz group without parity transformations). Under parity transformation the Weyl spinors transform into each other. The Dirac bispinor is connected with the Weyl bispinor by a unitary transformation to the Dirac basis, : The Dirac basis is the one most widely used in the literature. ==Expressions for Lorentz transformations of bispinors== A bispinor field transforms according to the rule : where is a Lorentz transformation. Here the coordinates of physical points are transformed according to , while , a matrix, is an element of the spinor representation (for spin ) of the Lorentz group. In the Weyl basis, explicit transformation matrices for a boost and for a rotation are the following:〔David Tong, (''Lectures on Quantum Field Theory'' ) (2012), Lecture 4〕 : : Here is the boost parameter, and represents rotation around the axis. are the Pauli matrices. The exponential is the exponential map, in this case the matrix exponential defined by putting the matrix into the usual power series for the exponential function. 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「Bispinor」の詳細全文を読む スポンサード リンク
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