Gravity from Discrete Interactions, a laboratory of ideas for field   theory
  The observed accelerated expansion of the universe is an indication that somehow, in some conditions, gravity may become a repulsive interaction. The very concept of discrete interactions, compatible with General Relativity as an effective theory of averaged fields, can handle this and other pressing problems without the need of searching for ad hoc exotic sources. Semi-quantum models of discrete interactions based on quantum exchanges between point-like masses are a rich laboratory for enlightening field interactions and classical-to-quantum transitions in field theory. A very simple version is presented for exhibiting how naturally it makes contact with inflation, dark matter and dark energy issues. 
Manoelito M de Souza
gr-qc hep-th