They key to exotic matter lies in quantum fluctuations, which give empty space a kind of fizziness. Quantum theory says that subatomic particles and their corresponding antiparticles are continually popping in and out of existence in the vacuum of empty space. Exotic matter might arise by suppressing this fizz, or as a physicist would say, by violating the averaged null energy condition (ANEC).
If this were to happen, quantum effects could give rise to tiny amounts of exotic matter. But how much is needed to sustain a wormhole?
That is what Visser and colleagues have now calculated. They find that, if the wormhole is designed carefully, "the total quantity of ANEC-violating matter can be made infinitesimally small". This makes a wormhole considerably easier to create.
http://www.nature.com/nsu/030527/030527-12.html
