Can extra dimensional effects allow wormholes without exotic matter?

Understand

We explore the existence of Lorentzian wormholes in the context of an effective on-brane, scalar-tensor theory of gravity.

• In such theories, the timelike convergence condition, which is always violated for wormholes, has contributions, via the field equations,from on-brane matter as well as from an effective geometric stress energy generated by a bulk-induced radion field.
• It is shown that, for a class of wormholes, the required on-brane matter, as seen by an on-brane observer in the Jordan frame, is not exotic and does not violate the Weak Energy Condition.
• The presence of the effective geometric stress energy in addition to on-brane matter, is largely responsible for creating this intriguing possibility.