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Localization and Causality for a free particle

N. Barat·J. C. Kimball
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Abstract

Theorems (most notably by Hegerfeldt) prove that an initially localized particle whose time evolution is determined by a positive Hamiltonian will violate causality. We argue that this apparent paradox is resolved for a free particle described by either the Dirac equation or the Klein-Gordon equation because such a particle cannot be localized in the sense required by the theorems.

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N. Barat, J. C. Kimball. 2003-02-28. Localization and Causality for a free particle. https://doi.org/10.1016/s0375-9601(02)01806-6

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