Talk:Delayed-choice quantum eraser

Technology Applications

Are there any technology applications that could be placed at the article Noting these are photons could you do radiography of a mineral sample through one path, then reobserve to cause the radiographic photon to travel a different path producing a different radiographic image sample This could be used to identify minerals or amplify the efficacy of computed tomography scanners providing fresh views with the same amount of photons

similarly could a hypercube be constructed Each vertice of the hypercube is a DeChQuEr Each vertice is made from quantum linked photons similar to the quantum camera described at new scientist magazine. physically motionizing the sides of the physics apparatus would change the spatial relation of the vertices to each other, which would effect the observed alternate precausal pathway to be longer thus creating a thing which described chronological moments at variable previousToobservation lengths That could be verified with quantifying the effects of motioing the physics apparatus. once it is noted that quantum linked photons at a DeChQuer actually traverse differnt areas of chronology with motioning a physical cube or slider rectangle Then things could be placed near the vertices or between them to find out if they effected the adjustable chronoprecausal lengths

Notably researchers have produced DeChQuEr with quantum linked photons Entanglement-enabled delayed choice experiment arXiv ... arxiv.org/pdf/1206.4348 arXiv by F Kaiser - ‎2012 - ‎Cited by 85 - ‎Related articles Jun 19, 2012 - Entanglement-enabled delayed choice experiment. Florian Kaiser,1 Thomas Coudreau,2 Perola Milman,2,3. Daniel B. Ostrowsky,1

Thus the geometries of those quantum linked photons with precausal have a technology basis

GA Review

This review is transcluded from Talk:Delayed choice quantum eraser/GA2. The edit link for this section can be used to add comments to the review.

Reviewer: David Eppstein (talk · contribs) 05:43, 6 February 2016 (UTC)

Reviewing. But this is likely to be a quick fail unless the "this section requires expansion" tag is dealt with, either by expanding the section or by determining that the tag is inappropriate. Also the title of the primary reference is listed incorrectly. How carefully did you check this before nominating? It is a bit troubling that the nominator has never edited the article in question and (per his self-description on his user page) does not seem to have the physics expertise needed to edit the technical parts of the article. —David Eppstein (talk) 05:43, 6 February 2016 (UTC)

Oh sorry. I must have misunderstood nomination. I just saw that it seemed significantly better than before. Is it usually supposed to be editors that nominate? TheKing44 (talk) 05:05, 7 February 2016 (UTC)

It doesn't have to be, but the process usually involves some back-and-forth, editing to fix the problems that the review turns up, so you have to be willing and able to edit the article. —David Eppstein (talk) 05:15, 7 February 2016 (UTC)

I'll see what I can do.TheKing44 (talk) 15:52, 7 February 2016 (UTC)

Still nothing, so I'm closing this for now as a quick fail. If you have time to address the cleanup tags and make a proper copyediting pass on the article, you can always nominate it again. —David Eppstein (talk) 22:17, 13 February 2016 (UTC)

re "clarification needed"

"Note in particular that an interference pattern may only be pulled out for observation after the idlers have been detected (i.e., at D1 or D2).[clarification needed]"

I think what the author is saying is that an interference pattern can't be determined until after a bunch of photons go through the experiment, and by that time of course the idler photons will have to have been detected. This is why backward causality isn't necessary for an explanation, btw--only entanglement. Though I wonder what happens if you make the apparatus long enough that you can send a whole lot of photons through before the idlers reach the detectors?

Oh, actually, let me correct that.

"By using a coincidence counter, the experimenters were able to isolate the entangled signal from photo-noise, recording only events where both signal and idler photons were detected (after compensating for the 8 ns delay). Refer to Figs 3 and 4.

When the experimenters looked at the signal photons whose entangled idlers were detected at D1 or D2, they detected interference patterns. However, when they looked at the signal photons whose entangled idlers were detected at D3 or D4, they detected simple diffraction patterns with no interference."

So, we only know if there's interference when we cross-correlate what's detected at the main detector with which way the idler photons went, so the idler photons have to be detected before the observation of interference.

(I still stand by my statement regarding backward causation and entanglement.)

Edit: Just for fun, here's a ChatGPT 5 exploration of my initial misunderstanding versus the actual reason, and then about metaphysical implications of entanglement under various interpretations. https://chatgpt.com/share/68e4d2da-dd18-800e-9b5e-968579f7c8de

 — Preceding unsigned comment added by 2600:1700:57EF:E10:3563:44E4:7976:3416 (talk) 08:50, 7 October 2025 (UTC) 

Edit 2: Here's the conversation furthered into more abstract territory, talking a bit more about MWT and QBism and how they might be unified, and then going into the deep end of a participatory universe: https://chatgpt.com/share/68e4d2da-dd18-800e-9b5e-968579f7c8de . In the end, I clarified my question about a possible experiment that shows interference patterns or not based on a change farther down the line without having to do coincidence counting, which chatgpt had misunderstood the first time.

Sorry if this is too irrelevant to post here, just one thing led to another. — Preceding unsigned comment added by 2600:1700:57EF:E10:3563:44E4:7976:3416 (talk) 10:27, 7 October 2025 (UTC)

— Preceding unsigned comment added by 2600:1700:57EF:E10:F5B9:EC0B:CD5B:5C03 (talk) 05:48, 7 October 2025 (UTC)