Is entanglement preserved on re-emission of photons

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    Entanglement Photons
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Discussion Overview

The discussion centers on the preservation of entanglement in photon pairs after they are absorbed and re-emitted through a phosphorescent coating. Participants explore the implications of their experimental setups involving UV entangled photon pairs and the conditions under which entanglement may or may not be maintained during the re-emission process.

Discussion Character

  • Debate/contested
  • Experimental/applied
  • Technical explanation

Main Points Raised

  • One participant claims to have created UV entangled photon pairs and questions whether entanglement is preserved when these photons are re-emitted through a phosphorescent coating.
  • Another participant challenges the validity of the first participant's claims, asking for experimental confirmation and suggesting that assumptions may be at play.
  • A participant references an online science journal and discusses the process of generating entangled photons from mercury lamps, asserting certainty about their results.
  • Concerns are raised about the complexity of generating entangled photons and the necessity of detailed experimental procedures beyond simply using a mercury lamp.
  • Some participants reference literature that discusses the generation of entangled photons from mercury and calcium, but disagreements arise regarding the interpretation of these references.
  • There is a discussion about the conservation of angular momentum in photon emissions and the conditions under which photons may be entangled.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the preservation of entanglement and the conditions necessary for generating entangled photon pairs. The discussion remains unresolved, with no consensus reached on the validity of the claims made or the interpretation of the references cited.

Contextual Notes

Participants highlight the importance of understanding the details of photon emission processes and the specific conditions required for entanglement, indicating that assumptions may lead to misunderstandings about the experimental outcomes.

sciencejournalist00
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What happens if I create entangled photon pairs and then pass them through a phosphorescent coating so they are absorbed and re-emitted?

Is entanglement preserved?

In my case, I have succeeded and created UV entangled photon pairs in my latest experiment but I could not see them with my naked eye so I used a phosphorescent coating to convert them to visible frequency.
 
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sciencejournalist00 said:
In my case, I have succeeded and created UV entangled photon pairs in my latest experiment ...

Really? What led you to this conclusion? Did you do any tests to confirm this? If so: can you describe the tests?

Or are you simply making an assumption?
 
DrChinese said:
Really? What led you to this conclusion? Did you do any tests to confirm this? If so: can you describe the tests?

Or are you simply making an assumption?

I repeated the experiment from an online science journal about getting these photons from mercury lamps. Mercury and calcium have an excited state with zero momentum and so is the ground state of each atom. The decay is double and the particles obtained are entangled.

http://arxiv.org/ftp/physics/papers/0503/0503052.pdf

I know it for certain. But I want the answer to my question - is the entanglement preserved?
 
sciencejournalist00 said:
I repeated the experiment from an online science journal about getting these photons from mercury lamps. Mercury and calcium have an excited state with zero momentum and so is the ground state of each atom. The decay is double and the particles obtained are entangled.

http://arxiv.org/ftp/physics/papers/0503/0503052.pdf

I know it for certain. ...

The reference does not indicate entangled photons are generated. They show the theoretical ability to create quantum phenomena, but little else.

Regardless, before you start telling us that you are generating entangled photons: tell us how you know for certain. You cannot make exaggerated claims and expect that they will not be challenged. I would recommend you retract your statement.

As to your question: What do you think? And why do you think it? Are phosphorescent photons going to retain their polarization through the process? What is phosphorescence? What are the intermediate electron states?
 
You missed the parts of the reference that contain the sentences

http://arxiv.org/ftp/physics/papers/0503/0503052.pdf
"Various ways can be used to generate entangled photons capable of exciting luminescent materials. Cascade atomic emission of photons can be used. Commonly used are the photons emitted by mercury lamps."

"Aluminate pigments and Zinc Sulfide pebbles were quantum entangled via photoexcitation with entangled photons from a mercury lamp"

And you missed this

https://books.google.ro/books?id=Gl...E#v=onepage&q=mercury atoms entangled&f=false

"From about 1990 onward, experimentalists replaced the calcium and mercury atom sources for entangled photons with a device called a spontaneous parametric down-converter."

See? Another reference telling mercury and calcium are sources of entangled photons.

https://www.quora.com/Why-does-excited-calcium-emit-entangled-photons-rather-than-unentangled-photons

"The excited state of calcium atom, that is used as entangled photon source, has zero angular momentum (J). As the ground state of a calcium atom also has J=0, angular momentum conservation forbids direct transition with single photon emission, as photon has spin 1. So the state decays with emission of two photons, via an intermediate J=1 state. As the intermediate state has very short lifetime, too short for any interaction to affect the direction of its spin, the spins of emitted photons must sum up to zero. This makes them entangled."
 
Last edited by a moderator:
sciencejournalist00 said:
You missed the parts of the reference that contain the sentences

http://arxiv.org/ftp/physics/papers/0503/0503052.pdf
"Various ways can be used to generate entangled photons capable of exciting luminescent materials. Cascade atomic emission of photons can be used. Commonly used are the photons emitted by mercury lamps."

No, I didn't miss anything. I keep telling you: having a mercury lamp does not mean you have entangled photon pairs. It is much more complicated than that. If you think these scientists just turn on a lamp and start counting, you are mistaken.

You must do a lot more. It is discouraging to see someone so obviously interested in the science ignore the details in the references. The details are the hard part, and they are critical.
 
DrChinese said:
No, I didn't miss anything. I keep telling you: having a mercury lamp does not mean you have entangled photon pairs. It is much more complicated than that. If you think these scientists just turn on a lamp and start counting, you are mistaken.

You must do a lot more. It is discouraging to see someone so obviously interested in the science ignore the details in the references. The details are the hard part, and they are critical.

As much as you would want mercury atoms to emit single independent photons, they cannot because their electronic shell forbids them to. Angular Momentum has to be conserved between the excited state J = 0 and the ground state J = 0.

The other part is that not any two emitted photons from a mercury lamp are entangled, only the photons emitted by the same atom. But I don't care about that in my setup.
 
You are talking too much and listening too little in this and some other threads.
This thread is closed.
 

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