Science
In reply to the discussion: Quantum Entanglement, Dark Counts, Coincidence Detection [View all]idkiigmy
(2 posts)Last edited Sun May 11, 2014, 02:00 PM - Edit history (1)
This is a fascinating and educational exchange - mindwalker_i and caraher, thank you! I especially congratulate you on discussing Dopfer/FTL without descending into preadolescent venom like many other threads.
I think caraher's explanation of the indispensability of the coincidence counter must be right, due to causality, the No-Communication Theorem, and most basically the fact the Zeilinger himself hasn't made any grand claims. Still, after reading about so many different ways of spawning entangled pairs and of detecting interference, it is counterintuitive in its own way that FTL communication via interference-checking wouldn't work. So I completely agree that mindwalker_i's (and Cramer's) experiment is worth attempting.
Aside from an update on that work, I was going to ask why a similar approach couldn't be applied to Walborn's quantum eraser experiment - using insertion of the linear polarizer at Dp to trigger an interference pattern at Ds. But it seems the diagrams there conceal the use of yet another coincidence counter. They're everywhere!
Finally, David Ellerman's paper on "why delayed choice experiments do NOT imply retrocausality" may be worth a look for its take on the key role of coincidence counters.
(Disclaimer: I'm not a physicist)
PS I updated the Ellerman link above to a more up-to-date revision of the same paper, hosted on his own site.