EPR effect in gravitational field: nature of non-locality

The realization of the Einstein-Podolsky-Rosen effect by the correlation of spin projections of two particles created in the decay of a single scalar particle is considered for particles propagating in gravitational field. Th e absence of a global definition of spatial directions makes it unclear whe ther the correlation may exist in this case and, if yes, what directions in distant regions must be correlated, It is shown that in a gravitational fi eld an approximate correlation may exist and the correlated directions are connected with each other by the parallel transport along the world lines o f the particles. The reason for this is that the actual origin of the quant um non-locality is founded in local processes. (C) 2000 Elsevier Science B, V, All rights reserved.