- #1
entropy1
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This may seem an odd question, but I'd really like to find out: is there proof that photons actually exist?
Proof Photons Exist? Evidence & Facts
In summary, the conversation discusses the existence of photons and whether it can be proven through experimental results or if it is only an assumption. The person suggests that the existence of photons is highly probable based on the results of the double slit experiment and the application of quantum mechanics to electromagnetic fields. It is also mentioned that the idea of photons being an artifact of decoherence has been considered, but without any quantitative calculations or testable predictions, it remains a mere speculation.
- #2
newjerseyrunner
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Well, we can produce and detect individual photons. Google the double slit experiment, light always shows up in packets.
- #3
entropy1
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newjerseyrunner said:
Yes, I know. But I was wondering if that could be explained by the packets being an artefact of decoherence in the measurement apparatus that 'flips' to a certain measured value...
- #4
Vanadium 50
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No. Proof is a mathematical term, not a scientific one.
- #5
entropy1
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Vanadium 50 said:
So the existence of photons is an assumption or something? (can't find the right word.
)- #6
DrChinese
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How about this (again, proof is in the eye of the beholder):
http://people.whitman.edu/~beckmk/QM/grangier/Thorn_ajp.pdf
http://people.whitman.edu/~beckmk/QM/grangier/Thorn_ajp.pdf
- #7
Nugatory
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It is an assumption that has an extremely high probability of being correct.entropy1 said:So the existence of photons is an assumption or something? (can't find the right word.
We have experimental results that suggest that electromagnetic radiation always delivers its energy and momentum in discrete lumps at a single point when it interacts with matter. These results might be "an artifact of decoherence" if different detection technologies all happened to have different artifacts that somehow ended up yielding the same ##E=h\nu## relationship between frequency and energy delivered per chunk. However, we wouldn't have artifacts of decoherence unless we have decoherence, and we wouldn't have decoherence if we weren't using QM, so we're accepting at least parts of QM. And if we just apply QM to electromagnetic fields, we find that QM predicts the existence of quantized disturbances of the field that interact with matter, including our measurement apparatus, in exactly the way that we have observed.
So there are two interpretations of these facts:
1) QM is right enough to produce these "artifacts of decoherence" AND these artifacts exist (although no has presented a rigorous description of them that predicts any experimental results) AND there's something wrong with QM when we apply it to electromagnetic fields, such that the prediction that photons exist is wrong AND no one has noticed the error in the math in the past 75 years AND all of the many different experiments and detectors that we use to study the exchange of energy and momentum between matter are all flawed in different ways AND despite the different mechanisms the flawed results all happen to be consistent with the quantum electrodynamical prediction.
2) The things our instruments are detecting are the photons that QED predicts.
I can assume that #1 is correct, or I can assume that #2 is correct. I can't prove anything... But I know which way I'm betting.
- #8
entropy1
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Nugatory said:
I get that!
Has there ever been considered that photons may be artefacts of decoherence though? (wondering... )- #9
Nugatory
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Yes. You just did.entropy1 said:I get that!
Now, if anyone were to go from "consider" to a quantitative calculation that matches the existing experimental support for quantum electrodynamics, and makes at least one testable prediction that QED does not... Then it would be part of the empirical science of physics. Until then, this thread is closed.
1. How do we know that photons exist?
Photons were first theorized by Albert Einstein in 1905. However, their existence was not confirmed until 1923 through the work of American physicist Arthur Compton, who demonstrated the particle-like nature of light through his experiments with X-rays.
2. What evidence do we have for the existence of photons?
There is a vast amount of evidence supporting the existence of photons. One of the most compelling is the photoelectric effect, which shows that light can cause the ejection of electrons from a metal surface. This phenomenon can only be explained by the particle-like nature of light, as proposed by Einstein.
3. How are photons different from other particles?
Photons are unique because they have properties of both particles and waves. They have no mass and travel at the speed of light, but also exhibit wave-like behavior, such as interference and diffraction. This duality is what makes photons distinct from other particles.
4. Can we observe photons directly?
No, we cannot observe photons directly because they have no mass and do not interact with matter. However, we can detect their presence through their interactions with other particles or by their effects, such as the emission of light or heat.
5. Are there any practical applications of understanding the existence of photons?
Yes, the understanding of photons has led to numerous practical applications, such as solar panels, lasers, and fiber-optic communication. The properties of photons also play a crucial role in fields like photography, astronomy, and medical imaging.
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