## Conservation laws in theories with universal gravity/matter coupling    [PDF]

Olivier Minazzoli
In this paper, we investigate the conservation laws of different type of particles in theories with a universal gravity/matter coupling. The result brings new insights about previous studies on universal gravity/matter theories. Especially, the paper demonstrates that for perfect fluids, there is an equivalence between the assumption $\L_m=-\epsilon$, where $\epsilon$ is the total energy density; and the assumption that the matter fluid current is conserved ($\nabla_\sigma (\rho u^\sigma)=0$, where $\rho$ is the rest mass density). However, the main result is given in the general case where one does not make any assumption on the conservation of the matter fluid current.
View original: http://arxiv.org/abs/1307.1590