%0 Journal Article
%T The Role of Density of Physical Variable
%A Eliahu Comay
%J Open Access Library Journal
%V 9
%N 4
%P 1-10
%@ 2333-9721
%D 2022
%I Open Access Library
%R 10.4236/oalib.1108572
%X The concept of density in quantum theories of an elementary particle is discussed. Density is, at least implicitly, recognized in contemporary textbooks on quantum field theories, where the Noether theorem is utilized for a derivation of a conserved 4-current <i>j</i><sub>,¦Ì</sub><sup style="margin-left:-10px;">¦Ì</sup>=0 and a conserved energy-momentum tensor T<sub>,¦Í</sub><sup style="margin-left:-10px;">¦Ì¦Í</sup>=0. Here the component <em>j</em><sup>0</sup> is the particle¡¯s density and the components T<sup>¦Ì0</sup> are the energy-momentum density. The novelty of this work is the analysis of the particle¡¯s density and the energy-momentum density of these expressions and their application to several specific quantum theories. As of today, these tasks have not been adequately accomplished in contemporary textbooks. The results show that the first-order Dirac theory of an elementary massive spin-1/2 particle yields consistent results. In contrast, second- order quantum theories, such as the Klein-Gordon theory, the electroweak theory of W<sup>¡À</sup>, Z the  particles, and the Higgs boson theory are inherently wrong.
%K Physical Principles
%K Locality Attributes
%K Quantum Theories
%K Coherence Tests
%U http://www.oalib.com/paper/6771230