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It's not about disturbing the photon. If you observe it, your detector gets entangled with it. It's possible for the photon going through the left slit and going through the right slit to end up in the same state and interfere, but if you get a detector involved then one of those will set off the detector and the other won't, so they won't be in the same ...

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In the famous double-slit experiment using photons, you have a couple of configurations: Configuration A - 2 slits and 1 screen: After sending 1 photon at a time at the double slit, the photon hits the screen seemingly at random, but over time an interference pattern builds up. But each photon went through on its own, so there are no other photons for it ...

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Coherency of light in practice is not an either/or issue. Any light due to any source has some degree of coherence. Laser light has usually much higher coherence than light of a hot metal filament. Some degree of coherence means, in simple wording, that light waves at one point of space due to different parts of the source behave similarly (they have ...

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The situation is entirely different from the double slit experiment! In the double slit experiment, one electron propagates through the slits, its parts interfere, thus we have a density matrix like (this prepares a pure state $\lvert\psi\rangle = \frac{1}{\sqrt{2}} (\lvert 1 \rangle + \lvert 2 \rangle)$):  \rho = \frac 1 2 \begin{pmatrix} 1 & 1 \\ 1 ...

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The reason D is the "correct" answer, is because the key word best, is used. Although any answer may not be 100% correct, if at least one of the answers is better than the others, then that would make it the correct answer. A and B are eliminated because the amplitude should decrease as one moves away from the XY center line. C is eliminated because it ...

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There are two ways to look at light, classical and quantum mechanical. Electromagnetic waves given by the classical solutions of Maxwell's equations will have interference patterns as predicted mathematically from the sinusoid form of the solutions. Are we working in the double slit argumentation with destructive interference arguments too? Young has ...

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The reason for the interference pattern is that photon's location in not well defined, the presence of photon in particular place can be determined by probability and this probability is presented as a wave. Probability distributions have the same meaning classically and quantum mechanically.There is a distribution for life expectancy for example, ...

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The pattern on the screen depends on where before the slit you measure the particles. If you measure the particle's position in a way, that it will propagate on in a way that will cover both slits later on, then you will just see the interference pattern as before. If you measure directly before the slits, the results will be (almost) the same as when ...

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We all know that if you shoot a single particle at the slits, the probability distribution that you will find on the screen after multiple trials will be that associated with a wave-like entity (interference pattern). Yes, you see a parttern like this one, courtesy of Brown University: Note though that each photon has energy E=hf or E=hc/λ. It has a ...

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On the screen you will detect particles always. But they won't form fringes, when you disturb them. If you do this before the slits edges, the result of seeing fringes or not depends from the result of your disturbance. For example, if you broaden the light beam, you are working against your apparatus which contains a collimator or a point-like light source. ...

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I could give a shorter then the other answers because of a different understanding how a double slit works. See my questions and answers in this forum. Every photon with its E and B field components get into interaction with the surface electrons from the slits material. Their field is quantized and this we see as fringes. Diffraction we not only get behind ...

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Will the pattern the 1 million entangled photons (An) created on the right screen in case 1), be discernible from the pattern in case 2), in the sense of being able to state with high probability which of the 2 cases applies, by analyzing the distribution of the photons (An), which hit the screen after passing through the right slit? No, the pattern of the ...

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Your question is muddled and unclear (in my professional opinion - you may think otherwise and that's OK), but I think I can make one thing clearer. If you have two entangled systems, $A$ and $B$, and perform independent experiments on either side, then nothing about the choice of experiment you perform on $B$ will have any effect on the local results from ...

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I suggest the book Consistent Quantum Theory by Robert Griffiths. In the book he gives physical interpretation of the math operations such as wave function collapse in a consistent way, the result is a cleaner, simpler framework without the common conceptual difficulty people get when interpreting quantum theory slightly incorrectly.

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As an experimental physicist, I go back to basics: Here is a double slit experiment a single photon at a time: The top panel shows dots from single photons coming in at the slits. The others the slow accumulation by which an interference pattern appears. That is what the experiment shows, dots like one would expect from single particles, ...

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As in John Rennie's answer we cannot describe the photon as being in a superposition of "going through different slits" states. But there is a sense wherein the answer to your question "Is a photon always in a state of superposition while traveling through space?" is almost always "yes". And the answer depends on a choice of co-ordinates. To answer the ...

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It basically boils down to this. Looking at a flying electron through a camera, there is no interference. Nothing special. But not trying to find which slit it went through and gradually observing the electrons to hit the detector there is interference pattern. In other words, when trying to find which slit the electron went through, wave function collapses ...

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