Delayed Choice Experiment

Most recent answer: 09/02/2016

Q:
I tried to understand the experiment more. In the following youtube video. the demonstration indicated that an entangled photon arrived at D0 while its partner arrived at, lets say D2 or D3 later on. I dont know why an already entangled single photon can leave interference data on D0. Isn't A PAIR of it can be form interference wave ? ( I think i missing some very basic physic knowledge...) Thank you!!video start by 6:54https://youtu.be/KnpCH9VRvPg?t=6m54s P.s. a physics beginner
- monique (age 30)
hong kong
A:

The site's detailed description of the experiment is quite nice, with good illustrations. The words used are consistently mixed up. They use classical-sounding descriptions of photons as objects that have specific locations, etc. When it turns out those non-quantum descriptions are incorrect, they jump to the conclusion that "idealism" must be right and "materialism" must be wrong. Those are vague words. What we do know from experimental results on entanglement (search for "Bell Inequalities" here.) is that non-conspiratorial local realism is wrong. That's a very big deal by itself, without embellishment.

Mike W.


(published on 09/02/2016)