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exmarine
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Is there any experimental evidence that photons can transmit negative momentum? After all, there is also a negative root: E^2 = (pc)^2 + (mc^2)^2
exmarine said:OK, how about this. Can a photon ever transmit momentum in the opposite direction of its propagation?
Maybe if the body hit by the photon had negative mass (the body would accelerate in the opposite direction of the force on it), but this is just speculation because negative mass doesn't exist.exmarine said:OK, how about this. Can a photon ever transmit momentum in the opposite direction of its propagation?
exmarine said:OK, how about this. Can a photon ever transmit momentum in the opposite direction of its propagation?
Vanadium 50 said:I'm still trying to envision a photon (or, for that matter, anything) moving in one direction, but its momentum pointing opposite.
exmarine said:You guys are way ahead of me, obviously. One of the things that provoked my question was Feynman rambling on and on about all the wondrous things that photons do. For example, “the nucleus keeps its electrons close by, by exchanging photons with its electrons”. I don’t feel like looking up an exact quote right now, but that’s pretty close. Well, doesn’t that require that those exchanging photons transmit negative momentum to produce attractive forces?
Thanks for all the responses.
Guido Diforti said:in Einstein's own words:
"[...]In every elementary process of absorption or emission a momentum of absolute magnitude ## \frac{h \nu}{c} ## is transferred to the molecule "
The momentum is in the direction of the movement of the photon during the absorption and in the opposite direction during emission.
Yes, according to the laws of quantum mechanics, photons can have negative momentum. This is because photons are massless particles and their momentum is determined by their frequency and wavelength.
The concept of negative momentum is a result of the wave-particle duality of photons. As a wave, photons can have negative momentum when they interfere with other waves, cancelling out their positive momentum.
Negative momentum does not affect the speed or direction of photons, but it can impact their interactions with other particles. For example, photons with negative momentum can be absorbed by atoms and cause them to move in the opposite direction of the photon's original momentum.
No, negative momentum can also be observed in other particles with wave-like properties, such as electrons and protons. However, it is most commonly associated with photons due to their massless nature and role in electromagnetic interactions.
The concept of negative momentum in photons has been utilized in various fields of research, such as optical trapping and optical tweezers. It has also been studied in the context of quantum information and quantum computing.