Is photon-photon annihilation possible in an optical fiber?

In summary, a report has claimed the possibility of photon-photon annihilation through a specific experiment involving the collision of two photons and a third particle of light. The researchers claim that this phenomenon can occur regularly and is essential for their reported teleportation. However, some have questioned the validity of this claim, stating that the experiment relies on absorption in the material and would not work in a vacuum. The use of optical fibers in the experiment has also been noted as unusual, as they are typically avoided in research due to their high absorption rates.
  • #1
Larry Pendarvis
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Consider this report:

http://www.physics-astronomy.com/2015/01/quantum-teleportation-of-subatomic.html
"Then, the researchers shot a third particle of light at the photon traveling down the cable. When the two collided, they obliterated each other. Though both photons vanished, the quantum information from the collision appeared in the crystal that held the second entangled photon."
There have been several reports of this result, all claiming photon-photon annihilation.
Is that possible? I am not asking if it is rare, I am asking if it is at all possible. The two photons that annihilated each other were not in this case even entangled.
If it is possible (however rare) for a neutrino and an antineutrino to annihilate giving a photon pair, then the time reversal would be photon-photon annihilation... but I'd guess you would have to get the phase just right. In which case you would not need the MEV energy of an electron-positron pair, but only the rest-mass energy of twice the neutrino, meaning that very-long-wavelength photons would work.

Is this result some kind of artifact of being in an optical fiber? The researchers do not seem to have any concern for conservation of energy; they do not mention what products of the annihilation there might be, the photons simply vanish, in their view.
 
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  • #2
Photon-photon interactions in vacuum are unlikely, but possible. There are concepts of a photon-photon collider (e.g. http://www.nature.com/nphoton/journal/v8/n6/full/nphoton.2014.95.html), but it would be expensive and the scientific use is probably not so great.
Electron/positron pairs would be the most interesting result (starting at 1 MeV center of mass energy), the reaction to neutrinos (starting somewhere below 1 eV) would be extremely rare and impossible to observe.

In matter, light behaves different, and two photons can go missing simply by absorption in the material, for example. This has nothing to do with the vacuum process.
 
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  • #3
mfb said:
Photon-photon interactions in vacuum are unlikely, but possible. There are concepts of a photon-photon collider (e.g. http://www.nature.com/nphoton/journal/v8/n6/full/nphoton.2014.95.html), but it would be expensive and the scientific use is probably not so great.
Electron/positron pairs would be the most interesting result (starting at 1 MeV center of mass energy), the reaction to neutrinos (starting somewhere below 1 eV) would be extremely rare and impossible to observe.

In matter, light behaves different, and two photons can go missing simply by absorption in the material, for example. This has nothing to do with the vacuum process.
But this report stated clearly that the disappearance was the result of annihilation; the third photon was what annihilated the other one. This was essential to the claimed teleportation. What is more, the experiment seems to have been able to do this on a regular basis, so it can't be rare at all.
 
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  • #4
Larry Pendarvis said:
But this report stated clearly that the disappearance was the result of annihilation
No I don't think so.
There is also two-photon microscopy where two photons get absorbed ("vanish") together.

The entanglement of one of the photon does not change anything. Yes the third photon gets the state from a different photon - so what. Interesting for entanglement, but irrelevant for the absorption process.

And again, this has nothing to do with photon-photon interactions in a vacuum.
 
  • #5
mfb said:
No I don't think so.
There is also two-photon microscopy where two photons get absorbed ("vanish") together.

The entanglement of one of the photon does not change anything. Yes the third photon gets the state from a different photon - so what. Interesting for entanglement, but irrelevant for the absorption process.
I am pretty sure that the report did make that claim. The photon would not have "vanished" without that third photon, otherwise why did they bother? And the word that was used was Obliterated, which I can't find a definition for.
So what was going on there was simply some kind of double-absorption that would not occur unless they fired that third photon, is that what you are saying? And the same experiment in a vacuum could not possibly have that result.
 
  • #6
Larry Pendarvis said:
The photon would not have "vanished" without that third photon, otherwise why did they bother?
It would have, but then there would be nothing interesting to study.

Larry Pendarvis said:
And the same experiment in a vacuum could not possibly have that result.
Yes. The material is absolutely necessary for the experiment they did.
 
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  • #7
mfb said:
It would have, but then there would be nothing interesting to study.

Yes. The material is absolutely necessary for the experiment they did.
Usually one does one's best to reduce absorption in an optical fiber. Here they rely on it.
 

What is photon-photon annihilation?

Photon-photon annihilation is a process in which two photons collide and are completely converted into other elementary particles, such as electron-positron pairs.

What conditions are necessary for photon-photon annihilation to occur?

Photon-photon annihilation can occur when two photons have enough energy to produce the desired particles. This typically requires high-energy photons, such as those found in particle accelerators or in extreme astrophysical environments.

How is photon-photon annihilation different from photon-electron interactions?

Photon-photon annihilation involves the collision of two photons, while photon-electron interactions involve the interaction of a photon with an electron. In photon-photon annihilation, both photons are completely absorbed and converted into other particles, whereas in photon-electron interactions, the photon may be scattered or absorbed by the electron.

What is the significance of studying photon-photon annihilation?

Studying photon-photon annihilation can provide insights into the fundamental forces and particles of the universe. It can also help us understand the behavior of matter and energy in extreme environments, such as in the early universe or in the vicinity of black holes.

Can photon-photon annihilation be harnessed for practical applications?

While photon-photon annihilation is currently not used for any practical applications, research in this area could potentially lead to new technologies, such as high-energy particle accelerators or advanced imaging techniques.

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