In Mandel et Al's most famous experiment (Fig 6 at [url]http://student.science.nus.edu.sg/~g0203645/Atomic%20Molecular%20and%20Optical%20Physics/Quantum%20effects%20in%20one-photon%20and%20two-photon%20interference.pdf) the signal beams from two coherent downconverters are observed to interfere only if the two corresponding idler beams are allowed to interfere.
Let's say that the a blocking object is inserted or removed in front of idler beam 1 at point A. Let us also say that the signal beams are detected at point B.
The direct distance between A and B is x light seconds, and the distance travelled by the idler 1 light beam from the 1 downconverter plus the distance travelled by the signal 1 beam from the 1 downconverter to B is y light seconds.
When the object is inserted/removed at A, how long does it take for the interference pattern at B to disappear/appear ?
2) x seconds later, or
3) y seconds later ?
(I know that the detector needs to move back and forth to see interference patterns, but assume it can move back and forth and record very quickly).
The above is question 1.
Since light travels at the speed of light, and from Relativity, something travelling at the speed of light experiences simultaneously different times (unlike all less-than-light-speed particles/waves), does it make any sense to say that light communicates and interferes with itself at what an outside inertial observer would call different times, due to those different times being experienced by the light beam simultaneously (ie can General Relativity's understanding of the light beams experience of simultaneous time explain some of the Quantum results seen in Question 1) ?
(and is there a good [very] basic paper which explains the link ?)