Alexandru Proca (1897-1955) and his equation of the massive vector boson field

This text is a short biography of A.Proca, a romanian-born physicist, who was attracted by fundamental problems such as the intimate nature of light quanta, the atomicity of entropy and even of time, he was one of the first thinker about discontinuous spatio-temporal frame. In 1925, M.Curie offered him his first job in her radium institute where he was assigned to make measurements of beta rays emitted by thorium descendants. He left the radium institute to pursue his natural calling towards theoretical physics. A major work of A.Proca was the extension of the Maxwell equations to the quantum field theory. It was Proca's equations that rendered Yukawa's genial intuition, about particles mediating interactions, the theoretical ground suitable for a spin-1 particle. The possibility and effects of a non-zero photon rest mass is incorporated into the Proca equations. The Einstein-Proca equations, describing a spin-1 massive vector field in general relativity have been studied in the static spherically-symmetric case. It has been shown that a special case of the gauge theory of gravity is effectively equivalent to the coupled Einstein-Proca theory. The Einstein-Proca equations are frequently discussed in connection with dark matter gravitational interactions. At the level of string theories there are hints that non-Riemannian models, such as Einstein-Proca-Weyl theories may be used to account for dark matter. All these implications show that Proca's heritage is well established. (A.C.)