About Majorana's Unpublished Manuscripts on Relativistic Quantum Theory for Particles of Any Spin

Abstract

In this paper we analyze the formal and conceptual steps made by Ettore Majorana in a wide set of unpublished (handwritten) manuscripts (Quaderni, Fascicoli, Volumetti) written in later 20's and earlier 30's where, starting from the Dirac equation for spin-1/2 particles, he developed quantum relativistic wave equations for different (integer and half-integer) spins. In such a way Majorana obtained a Dirac-like equation for the photon and an infinite component quantum field theory for particles of any spin, thus anticipating the modern supersymmetry and string theories.