My question is similar to Questions About The Delayed Choice Quantum Eraser Experiment. You may read this question and related answers first (or not).
My question is, in the delayed eraser setup, if I completely remove all the D1/D2/D3/D4 parts and only record D0, what will D0 be like?
Shouldn't it be an interfered pattern?
When I add in D1/D2/D3/D4 and all related apparatus for the entangled idler photons, then D0 will change into no interference can be seen.
Is my understanding right?
If it's right, then after D0 is detected, I quickly remove all the apparatus for D1-D4, before the entangled photon touches them, what will the D0 pattern be like?