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Does someone have access to Vantablack? Its usage is currently restricted for public use.I'd like to see if single edge diffraction can still occur when the obstacle absorb more than 99.9% of the light hitting its surface.I also want to see double edge diffraction, or widely known as single slit diffraction with aperture covered by Vantablack.
//www.youtube.com/watch?v=nAk7gvXWB7kFinally finished the video demonstrating single and double thin wire diffraction-interference experiment.
In this video, diffraction-Interference pattern by single and double needles are traced from the light source to the screen several meters away. The results are rarely mentioned in physics education materials.
Demonstration of another type of diffraction involving total internal reflection
I changed this light by observing itThis video is about the quantum eraser experiment. Understanding this experiment helps us understand the measurement problem in quantum physics, and it might even give us a clue for how to solve it.
Doesn't this just show the trivial fact that interference between beams of light with orthogonal polarization doesn't create the constructive/destructive interference pattern, and filtering both beams through the same filter restores the pattern because now the peaks and valleys are in the same plane?
Superposition between light beams with orthogonal polarization generally produces elliptically polarized light, which depends on the phase difference at the point on the screen. When they have the same phase, the result is linearly polarized. When the phase difference is 90 degrees, the result is circularly polarized.
"i changed this light by observing it" is actually more like "I changed this light by changing it" more precisely, polarizing it.
You didn't really "change the light by observing it". The first filters didn't block the light, it just changed the polarization so it doesn't interfere with the light from the other slit. Its still there, and the second filter takes a part of both light waves and causes them to interfere and you get the pattern. It doesn't have anything to do with observation or multiverses. The lights going to shine even if your not in the room.
After many years trying to follow as much as I can as much of the interpretations of quantum mechanics as I can, as a lay person who at best is just an open-minded enthusiast, I am reaching more and more the conclusion that there is a very serious issue in all this, an issue that has become a full-blown crisis in the realm of not only how quantum mechanics is perceived, but also by how it is taught, not just to physics students but also to us lay people who require generalizations and analogies, even metaphorical examples, in order to understand and internalize what we are dealing here. The issue lies with the fact that physicists themselves often perceive physics by taking for granted many interpretations that were given to them ready-made by other physicists that came before them, and since these are things that lie outside our everyday experience and cannot be mentally visualized, the "shut up and calculate" approach seems like best way to go, even if this means just regurgitating mistakes made by others and others before them. I think there is a big discrepancy in our understanding of quantum physics between the ontological reality and a so-called "configuration" reality, that framework created for mathematical convenience which does not actually mean it is a literal rapresentation of physical reality. I do not believe that particles are literally in many or all places at once, or go back in time or take all possible paths that exist at the same time, or that every choice creates multiple realities that branch out ad infinitum as an "all that can exist, does exist" hypothesis. I do not believe in the esoterism our imagination has given to the concept of physical reality, especially because these are things that stem from us NOT KNOWING what goes on under the hood, and the less sure we are, the more we tend to take it for granted and even misunderstand the difference between mathematics as a tool for understanding reality and physical reality in itself. I find it ridiculous when I see smart people, academics and even physicists claiming that the wavefunction is physically real, meaning it exists in the same 3D space that we do, I get the fascination with the unknown but we are not dealing with magic here. I never took the wavefunction for something more than an abstract computational tool that existed in abstract spaces, there where Hilbert spaces or the 4th dimension exist, and never took it literally. If you think about it for more than a minute you can see how absurd it is. Adding to all this many mistakes in science communication and we have a reality with media articles with big clickbaity titles "Scientists create a wormhole in their computer drive" or "Scientists discover that time exists as an arrow in both directions, so it's confirmed, time travel in the past exists" and ridiculous things like that. We should not take anything for granted, especially when it comes to how we should understand abstract concepts, even if it was told to us by Einstein or Feynman or whoever it may be, they were geniuses no doubt but they were human as much as we are and they understood the world as best as they could for the time that they lived. We should also not just "shut up and calculate" but strive to understand, not only the underlying framework and the toolkits but the meaning as well and how it all relates to the ontological reality where we exist. Quantum mechanics is at best an uncomplete rapresentation of reality, sure it is the best we got but it's not the end of the line. Same as it is with General Relativity. So we must be careful and make sure we are not regurgitating the mistakes of others and internalize them as our own. Let us not become as arrogant and delusional as those fellas from the 1700s and the 1800s who declared that "finally we now know everything there is to know".
Does this experiment *actually* prove light is a particle?This video is about Richard Feynman's Quantum Electrodynamics (QED), which says that light is made of photons that go on all possible paths at once. The experiment in the video is from the following video from Veritasium. Even though I don't agree fully agree with their interpretation of the experiment, I think it's an excellent explanation of QED. Highly recommended!Edit: a lot of comments think that this effect only happened because of the smoke I used, or because this wasn?t done in a vacuum. Actually neither of those things should affect the result at all. It?s just that the smoke lets you see the whole beam, which is better for visualising it.I'm really excited to be making "Quantum Experiments from at Home" again If you have any ideas for experiments you want to see, let me know! https://www.youtube.com/playlist?list=PLg-OiIIbfPj3mDFx5zjVPtgiGwZMM4Erw
I was screaming this at the Veritassium video but I will tell this to you as well; Please do the same test, but make a small black tube (ideally with vantablack painted on the inside to kill all reflections) and put it at the end of the laser pointer. What results you get with THAT test is the interesting one. As you can see on you video, your eyes can see the bright green end of the laser pointer. The fact that you can SEE it means light is emitted in the direction. By putting a black tube to cover up any side spill, this is eliminated as a false positive.
Yea, like Veritassium's video this one fails to prove its point. If I can see the laser beam's origin in the mirror even when the laser pen is pointed obliquely it means the beam is not perfectly collimated. The aperture of the laser is functioning as a point source with an extremely wide angle. Additionally the beam itself functions as a long linear point source due to the random scattering through atmosphere. The experiment's results rely on there being an initial single path that all the photons should classically take, which we can then assume to be infinite paths, manipulate those paths, and show that we can make new "real" paths. If you can't ensure that the photons are directed into a single path initially, then the expected conclusion will not follow from the experiment.
That's the flaw with theorists - they never test things properly or think practically about phenomena like engineers do.
We must be careful not to let biases affect our analyses. Feynman and the founders of QM were strongly biased in favor of the particle model, and you can counter their bias by simply substituting the word "wave" for "particle" everywhere in Feynman's "all possible paths" description: it then says a wave travels all possible paths, which is at least as sensible as saying a particle travels all possible paths. Feynman's explanation "cancellation due to phase differences" obviously makes more sense for a wave than for a particle, since phase is a property of wave motion. As Mithuna pointed out near the end of the video, the only particle-like behavior of light happens when light is absorbed. (For example by an electron in a detector.) That's when it behaves nonclassically... its entire energy quantum is absorbed, whenever & wherever any of its energy is absorbed. But this nonclassical property doesn't imply the light was a particle -- its quantum of energy entirely located at a point or within a very small volume of space -- a moment before it was absorbed, because there's a logical alternative: the quantum of energy is distributed in space (as a wave) while light travels, and the Locality axiom is violated when some of the energy jumps to the point of absorption.
We may not confuse. A laserpointer isnt a perfect tool, its a 99% or 98% or we dont know exactly laser, including light scattering. Dont confuse that. Further on ask yourself: why do you see the laserbeams. Everyone understands, after a small self-reflection :-) : We see the nicely green beam because it is travelling through your dusty air. And its scattering light around that bright that its apprearing nearly as bright seen through the cam as the point where it meets a white wall:And there is a 2nd source of possible misinterprtation: The camera setting is adjusted to a dark environment, the laser reflections, in contrast, are all maximally controlled and their relative strength is not differentiated from one another or is not shown truthfully.The experimental setup for scientific investigation must control all this issues.For a demonstration its important do show the impact of unexplained side effects explicitely.Such optic experiments around the natur of light are really important for a better understanding of its nature and it is very important to stay very accurate and self-critical to avoid hasty conclusions. Better ask;`: What could be wrong with my conclusion, what can i do to avoid it.
Feynman's like, "light is a particle. But not one particle, every possible particle. And not regular particles, but particles that can cancel each other out. But definitely not a wave!"
Does light take all possible paths at the same time?0:00 What path does light travel?2:40 Black Body Radiation6:47 How did Planck solve the ultraviolet catastrophe?9:42 The Quantum of Action13:25 De Broglie?s Hypothesis 15:16 The Double Slit Experiment20:00 How Feynman Did Quantum Mechanics25:01 Proof That Light Takes Every Path31:16 The Theory of Everything
Perfect! remember chatting with Casper (Veritasium?s producer) while their video was still in the works.And when he casually said, ?Particles do take all possible paths,? I was like??Wait, what? That?s just a model!?I mean, come on?all of physics is just models.We never know what?s actually real.We just build ideas that match the universe?s behavior and use them to predict stuff, make cool tech, or just not die.Casper told me, ?Just watch the video.?And after watching it, I couldn?t stop thinking:?Wait? did they just prove this??Mind = blown.Turns out, the missing piece (as you and Mithuna beautifully pointed out) was the fact that the laser light spreads out?and that?s what makes the interference pattern make sense.So thank you. All these videos didn?t just explain things?it leveled up my entire mental model of how the universe works