Non-minimal curvature-matter couplings in modified gravity
  Recently, in the context of f(R) modified theories of gravity, it was shown that a curvature-matter coupling induces a non-vanishing covariant derivative of the energy-momentum, implying non-geodesic motion and, under appropriate conditions, leading to the appearance of an extra force. We study the implications of this proposal and discuss some directions for future research. 
Orfeu Bertolami, Tiberiu Harko, Francisco S. N. Lobo, Jorge P\'aramos