The Omega Effect as a Discriminant for Space-Time Foam

If there is CPT violation, the nature of entanglement for neutral meson pairs produced in meson factories may, on general grounds, be affected. The new form of entanglement is the omega effect. Gravitational decoherence, due to space-time foam, may be one route for deviations from CPT invariance. Two models of space-time foam are considered. One, based on non-critical string theory, is able to produce the new correlations in a natural way. The other, based on the paradigm of thermal-like baths, is shown to be surprisingly resistant to producing the effect even on exercising a total freedom of choice for the state of the bath