Swap Operators and Electric Charges of Fermions
  Electric Charges operator (ECO) in phase space formulation, proposed by Zenczykowski, is expressed in terms of a swap operator, in some expressions for possible physical interpretations. An expression of an ECO in terms of a swap operator makes sense to the eigenvalues of the swap operator. An ECO including all the fermions of the standard model (SM) is constructed. 
Christian Rakotonirina and Adolphe A. Ratiarison
hep-ph