Third order wave equation in Duffin-Kemmer-Petiau theory. Massive case

TL;DR

This paper refines the derivation of the third order wave equation in DKP theory using algebraic objects like the q-commutator and eta matrices, providing a more consistent framework and extending it to electromagnetic interactions.

Contribution

It introduces eta matrices and the q-commutator to systematically derive the third order wave equation in DKP theory, improving upon previous heuristic methods.

Findings

Successful algebraic reduction of the cubic root construction

Extension to electromagnetic interactions with minimal coupling

Analysis of solution singularities in the limit z → q

Abstract

Within the framework of the Duffin-Kemmer-Petiau (DKP) formalism a more consistent approach to the derivation of the third order wave equation obtained earlier by M. Nowakowski [Phys.Lett.A {\bf 244} (1998) 329] on the basis of heuristic considerations is suggested. For this purpose an additional algebraic object, the so-called $q$ - commutator ($q$ is a primitive cubic root of unity) and a new set of matrices $\eta_{\mu}$ instead of the original matrices $\beta_{\mu}$ of the DKP algebra are introduced. It is shown that in terms of these $\eta_{\mu}$ matrices we have succeeded in reducing a procedure of the construction of cubic root of the third order wave operator to a few simple algebraic transformations and to a certain operation of the passage to the limit $z \rightarrow q$, where $z$ is some complex deformation parameter entering into the definition of the $\eta$ - matrices. A corresponding generalization of the result obtained to the case of the interaction with an external electromagnetic field introduced through the minimal coupling scheme is carried out and a comparison with M. Nowakowski's result is performed. A detailed analysis of the general structure for a solution of the first order differential equation for the wave function $\psi(x; z)$ is performed and it is shown that the solution is singular in the $z \rightarrow q$ limit. The application to the problem of construction within the DKP approach of the path integral representation in parasuperspace for the propagator of a massive vector particle in a background gauge field is discussed.