My question requires an introduction, but I think it is important. I hope that it is not too long.

In the transactional interpretation of quantum mechanics (see link), inspired by the Wheeler–Feynman absorber theory, a transaction is formed between the emitter and absorber by a superposition of advanced and retarded waves. In a Minkowski diagram of such an interaction involving the emission and absorption of a particle, the emergence of the transaction does not occur at some particular location in space or some particular instant in time, but rather forms along the entire four – vector which connects the emission with the absorption locus. The transaction involves the interference of retarded and advanced waves.

The influence of the transaction in enforcing the correlations of the quantum events is both nonlocal and temporal. Due to this interference (destructive interference), there are no advanced (or retarded) waves before the emission of the particle and after its absorption, but constructive interference reinforces them (the retarded waves) between the emitter and the absorber (as points in space - time). Only the completion of this transaction facilitates the momentum and energy transfer between the emitter and absorber.

I emphasize that this happens in flat space – time (for type one transactions). My suggestion (and related question) is to study these phenomena in curved space – time. This would require quantum field theory in curved space – time (as a theoretical tool). In various EPR experiments (or experiments involving entangled laser beams), if the emitter or the absorber are in a curved space – time, there is a distinct possibility that the transaction involving the interference of advanced and retarded waves might not be perfect (as in flat space - time), and therefore some residual advanced waves might be present, that could be detected (the destructive interference that cancels them in flat space – time might not be complete in curved space - time).

In fact, a simple experiment (conceptually at least) as directing a laser beam towards a black hole might open the possibility of detecting advanced waves. Introducing this element of asymmetry in terms of the curvature of space – time in the emitter or absorber vicinity might open the possibility of detection of these advanced waves. I am not thinking about sending messages to the past (at the macroscopic level), with all the paradoxes that it implies, but rather setting up experiments where the only way nature can be consistent would be to “promote” low probability events to very likely events, a way to influence the probability distribution of events (as Professor John Cramer would say). This would be important in the context of computation with CTC's.

It is also worth mentioning that the equivalence principle opens the door towards simulating such environments by putting the emitter and/or absorber in accelerating systems (fast rotation for example). Experimental tests in order to detect advanced waves were proposed by Partridge (in 1973), Heron and Pegg (in 1974), Schmidt and Newman (in 1980), and others. The actual performed experiments were unsuccessful, but none of them took into account the curvature of space – time around the emitter and absorber (in the context of the transactional interpretation). Only a complete analysis of these proposed experiments in the context of quantum field theory in curved space – time could estimate the level of feasibility of my proposed experiments.

The experiments described are just a few the class of imaginable possibilities but the reader should get the point at this stage.

Would all this be possible?

http://www.npl.washington.edu/npl/int_rep/tiqm/TI_toc.html