Formation of wormholes in modified gravity: Exotic matter and stability

Abstract

This work addresses the question whether exotic matter is essential for the formation of wormholes in modified gravity theories. The basic property of wormhole geometry is the flaring-out condition at the throat which essentially states the violation of null energy condition for the matter threading the wormhole in Einstein gravity. In modified gravity theories, the field equations can be written as Einstein equations with two non-interacting fluids of which one is the usual fluid under consideration and the second term, called the effective matter, comes from the extra geometric terms of the theory. So it is interesting to examine whether normal fluid with restrictions on geometry satisfies the conditions for the formation of wormholes and their stability.