Localized States for Elementary Systems
- 1 July 1949
- journal article
- research article
- Published by American Physical Society (APS) in Reviews of Modern Physics
- Vol. 21 (3) , 400-406
- https://doi.org/10.1103/revmodphys.21.400
Abstract
It is attempted to formulate the properties of localized states on the basis of natural invariance requirements. Chief of these is that a state, localized at a certain point, becomes, after a translation, orthogonal to all the undisplaced states localized at that point. It is found that the required properties uniquely define the set of localized states for elementary systems of non-zero mass and arbitrary spin. The localized functions belong to a continuous spectrum of an operator which it is natural to call the position operator. This operator has automatically the property of preserving the positive energy character of the wave function to which it is applied (and it should be applied only to such wave functions). It is believed that the development here presented may have applications in the theory of elementary particles and of the collision matrix.This publication has 4 references indexed in Scilit:
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- Group Theoretical Discussion of Relativistic Wave EquationsProceedings of the National Academy of Sciences, 1948
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- On Unitary Representations of the Inhomogeneous Lorentz GroupAnnals of Mathematics, 1939