Wormhole geometries in f(R) modified theories of gravity

In this work, we construct traversable wormhole geometries in the context of f® modified theories of gravity. We impose that the matter threading the wormhole satisfies the energy conditions, so that it is the effective stress-energy tensor containing higher order curvature derivatives that is responsible for the null energy condition violation. Thus, the higher order curvature terms, interpreted as a gravitational fluid, sustain these non-standard wormhole geometries, fundamentally different from their counterparts in general relativity. In particular, by considering specific shape functions and several equations of state, exact solutions for f® are found.