Biphoton: Existence of layered or multiple entanglements

[Revolucien]

TL;DR Summary

exisitence of layered or multiple entanglements

I read this recent article describing photon quantum entanglement to produce higher resolution microscope. https://phys.org/news/2023-05-quantum-entanglement-photons-microscope-resolution.html
I am curious if quantum entanglement could exist in layers with a third or more entanglement feature. They specify that they call the two entangled photons a “biphoton”… is there a possibility of a tri- or quad- or more photon entanglement?

 

[vanhees71]

The scientific article is open access:

https://doi.org/10.1038/s41467-023-38191-4

 

[Revolucien]

The scientific article is open access:

https://doi.org/10.1038/s41467-023-38191-4

Vanhees71,
I appreciate the article. It is very interesting and describes a little more detail about the use for microscopy, but I was hoping to find something more about the possibility of compound or layered link involving multiple entanglements rather than a single connection.

The forum protocol automatically adjusted my post title to add “Using photon quantum entanglement to produce higher resolution microscope images” not the focus of my question, and I did not see where to change it.

The summary “existence of layered or multiple entanglements” is more to my original question…
“They specify that they call the two entangled photons a “biphoton”… is there a possibility of a tri- or quad- or more photon entanglement?"

 

[berkeman]

The forum protocol automatically adjusted my post title to add “Using photon quantum entanglement to produce higher resolution microscope images” not the focus of my question, and I did not see where to change it.

The summary “existence of layered or multiple entanglements” is more to my original question…

I have updated your thread title now to your new suggested version. In the future if you want your title updated, just click "Report" on your post and ask the Mentors to update the title.

 

[DrChinese]

“They specify that they call the two entangled photons a “biphoton”… is there a possibility of a tri- or quad- or more photon entanglement?"

Sure. There is no particular limit to the number of particles N that can be entangled. N=3 and N=4 get a lot of attention in terms of new papers coming out. Many papers even generalize theory to N>2. Actual experiments have been done with many permutations. Check out these links:

Two independent photon pairs versus four-photon entangled states in parametric down conversion
https://arxiv.org/abs/1508.01480
https://arxiv.org/pdf/1510.02665.pdf

Fair warning: these are advanced papers. And yes, it is also possible to entangle systems in multiple bases or degrees of freedom (what you might call "levels"). Also referred to as hyperentanglement.

 

[Revolucien]

DrChinese,
Thanks for the links... I got some reading to do.