Unraveling the physical meaning behind Elko’s dual structure

In this work, we shall analyse the necessity of a proper definition of the dual structure for Elko spinors and singular spinors in general. We examine in detail why the Dirac dual structure fails, and it is not functional for these cases, highlighting all the physical consequences of this misdirection. The approach considered here is different from the one usually taken in current literature. We pinpoint the shortcomings that this dual structure brings to particle interpretation and propagator structure, as well as the implications in non-locality and the existence of negative energy levels. This investigation furnishes a background for the successful achievements in the field associated with such proper dual formulation.