Phi for All Posted November 17, 2021 Posted November 17, 2021 8 hours ago, bangstrom said: I claimed that light emitted from a point and arriving at a point does not necessarily imply that light is a particle at that point because light as a wave can do the same. I answered your question before, Remember my repeated comments about transverse waves not spreading out and light no longer existing at its arrival so its point of arrival doesn’t imply that it ever was a particle? I have also answered similar questions but I don’t recall if they were from you or others and I responded by discussing the Afshar experiments, Poincaré's dot, the W-F absorber, and how light from one atom is only absorbed by a single atom. None of these demonstrate the particle nature of light. Poincaré's dot is worth expanding upon since it speaks directly to your question. Poincaré claimed that a spherical object placed directly in a narrow beam of light should completely block the passage of light, if light is a particle, but if the object is only slightly larger than the beam, light should be able to pass around the obstruction as a wave. Afshar and Flores performed similar experiments with a wire grid. Arago performed Poincaré's experiment using a metal bead on a string and he found that light went around the bead as a wave and landed as a bright dot exactly in the middle of the object’s shadow. So light as a wave can land as a point even if it has to curve around an obstruction. That is an example of light as a wave being emitted from a point and landing at a point. Light responds to its environment beyond what one could expect of light as a particle. Diffraction is one example. If light passes through a single slit it produces a diffraction pattern, If it passes through a double slit it produces an interference pattern, and if it passes through a triple slit, it produces an even more elaborate pattern. How does a photon passing through only one of a triple slit “know” how many slits are to its left or right and act accordingly? If a photon of light reflects from the surface of a frosted glass plate, it reflects a random angles. But if it reflects from a polished surface, it reflects at its angle of incidence. How can a single particle “know” if the area around it is rough or polished? Light responds to the wave like nature of its surroundings, and if those conditions favor arrival at a single point, it will arrive at a single point. That may be particle like behavior but it does not rule out the total wave like nature of light. ! Moderator Note You aren't ready for discussion. Whether conscious or not, you're using obfuscating tactics and tap-dancing around the actual point of discussion, which is to learn. Here we choose to tap into the exponential power of communicating the results of mainstream experimentation and observation. Guesswork has its place, but it needs to be forged in the fire of a proper methodology. You are just waving your hands and expecting this idea to fly. Thread closed, don't bring this subject up again because you obviously can't support it within our rules.
swansont Posted November 17, 2021 Posted November 17, 2021 9 hours ago, bangstrom said: I claimed that light emitted from a point and arriving at a point does not necessarily imply that light is a particle at that point because light as a wave can do the same. Yes, you claimed this. Where is the evidence that supports this claim? 9 hours ago, bangstrom said: I answered your question before, Remember my repeated comments about transverse waves not spreading out and light no longer existing at its arrival so its point of arrival doesn’t imply that it ever was a particle? I have also answered similar questions but I don’t recall if they were from you or others and I responded by discussing the Afshar experiments, Poincaré's dot, the W-F absorber, and how light from one atom is only absorbed by a single atom. None of these demonstrate the particle nature of light. Why would anyone discuss non-particle behavior when we’re trying to demonstrate particle behavior? (not that I know what you mean by Poincaré's dot or what W-F means. As far as light being absorbed by one atom, all you have done is deny that it’s relevant, but without any justification. Waves interact over an extended area. “Nuh-uh” isn’t a valid response. 9 hours ago, bangstrom said: Poincaré's dot is worth expanding upon since it speaks directly to your question. Poincaré claimed that a spherical object placed directly in a narrow beam of light should completely block the passage of light, if light is a particle, but if the object is only slightly larger than the beam, light should be able to pass around the obstruction as a wave. Afshar and Flores performed similar experiments with a wire grid. No Google hits for Poincaré's spot, which is a demonstration of wave behavior. Why would anyone use it as evidence of particle behavior? How is this a remotely reasonable expectation? 9 hours ago, bangstrom said: Arago performed Poincaré's experiment using a metal bead on a string and he found that light went around the bead as a wave and landed as a bright dot exactly in the middle of the object’s shadow. So light as a wave can land as a point even if it has to curve around an obstruction. That is an example of light as a wave being emitted from a point and landing at a point. Yes, Arago’s spot. 9 hours ago, bangstrom said: Light responds to its environment beyond what one could expect of light as a particle. Diffraction is one example. If light passes through a single slit it produces a diffraction pattern, If it passes through a double slit it produces an interference pattern, and if it passes through a triple slit, it produces an even more elaborate pattern. How does a photon passing through only one of a triple slit “know” how many slits are to its left or right and act accordingly? Diffraction is wave behavior. Again: so what? You appear to be rebutting a straw man - nobody has claimed that light (or quantum particles in general) always exhibits particle behavior. 9 hours ago, bangstrom said: If a photon of light reflects from the surface of a frosted glass plate, it reflects a random angles. But if it reflects from a polished surface, it reflects at its angle of incidence. How can a single particle “know” if the area around it is rough or polished? Light responds to the wave like nature of its surroundings, and if those conditions favor arrival at a single point, it will arrive at a single point. That may be particle like behavior but it does not rule out the total wave like nature of light. (emphasis added) Yes, actually, it does. If particles and wave has identical behavior we wouldn’t make a distinction The claim being rebutted is that light never acts like a particle. If you observe particle behavior, then it behaves like a particle. 1
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