[I_Am_Nous]

No, but there is a cool blending of the two concepts when light is bent by large gravity wells so that it actually shows the same star multiple times. When we observe which copied star "produced" a certain photon, it technically collapses the quantum possibilities backwards in time as that photon was emitted potentially billions of years ago.

[cypherpunks01]

I'm not sure about that. I suppose it really depends on your interpretation of the results, but I didn't think the cosmic interferometer experiment convinced physicists of retrocausality, by-and-large.

[I_Am_Nous]

Functionally it means we can trace a single photon back to the source which emanated it, lensed or unlensed. That said, if quantum effects are not bound by time or space technically the photon ALWAYS came from an individual source and our clarifying which one it came from just collapses the wave from superposition of where the photon could go to where it did go.

As I understand the double slit experiment, this is a fundamental property of light as a photon exhibits wave-particle duality. If so, retrocausality in this case would just mean the fundamental wave function can be collapsed into actuality without time or space being involved.

Am I far off base?

[rightbyte]

> it technically collapses the quantum possibilities backwards in time as that photon was emitted potentially billions of years ago

There is no way to verify that. Big parts of quantum physics is more or less pseudoscience.

[matkoniecz]

> Big parts of quantum physics is more or less pseudoscience.

[citation needed]

[I_Am_Nous]

Perhaps it could be verified using time delayed lensing experiments[1]?

1. https://www.nature.com/articles/s41550-021-01450-9

[rightbyte]

Seems like measuring "bending" of light, rather? But honestly I am not really qualified to say anything about astronomy.

[I_Am_Nous]

In this case it's light bending around a gravity well which produces multiple "copies" of the star, but the light from each copy arrives at different points in time.

So they could capture the light and attempt to capture the "same" light again later to try to verify or change the result they received.

I did some more reading about it after posting, and the original experiment was intended to test if light "chooses" to be a wave OR a particle in a way they could affect, and that it could only be one or the other at a time. The truth seems to be more that it acts as both at the same time and whatever sensor equipment you use to pick it up is what it acts like.