# Tag Info

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Does a spherical wave-front, as you describe it, require at minimum 2 spherical bursts from a single atom? If spherical wave-fronts form as energy bursts that are independent in nature, with time greater than 0 (t>0) between each burst, and each burst being equal in energy, then in order to adhere to E=hv, might determining the frequency and energy of a ...

8

It's tempting to think of the light as a little ball (the photon), and since little balls have a definite position the little ball has to be in a superposition of a state where it goes through one slit and a state where it goes through the other. However this is not a good description of what actually happens. The light is not a photon, and it's not a wave ...

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Plane wavefronts ensure that the field at the apertures are in phase and coherent and thus the interference pattern is produced (see Fig.1). Non planar input to an aperture equals a case where the point oscillators at the apertures are not in phase and depending on the coherence length of the incoming field, might not be coherent (see Fig.1). Thus, the ...

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Your idea is to do faster than light communication between the observer controlling the switch and the one reading D0. Right? If a message could be sent like that then the message would be a serie of "on" and "off". The observer at D0 should be able to tell using its readings when the switch is on or off. Whatever happens to the photons leaving the switch ...

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The change of the overall phase of the wave function, $\left|\Phi \right> \to e^{i\phi}\left|\Phi \right>$ is unphysical since they give the same expectation value for any observable operator. So, they represent the same physical state: indeed the space of physical states is not the Hilbert space, but rather it is the space of equivalence classes of ...

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(a)The problem with wave particle duality, in the test you propose, is that it has yet to be determined what is really going on in nature. One solution not yet accepted is that energy leaves the atom in the form of expanding spheres with definite gaps between the nested spheres, thus being Quantum (discrete) and also meeting E=hv because each sphere has the ...

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The big questions with this experiment is something else. It is about of recording of where The particule goes. On The Left ore right. Or Both. When is recording The particule is moving as a particule , no interference. But When it is no recording by sensors it has a wave behaviour. Moreover other experiments confirm That The light is Smart. It know That it ...

1

The interference pattern appears when the two slits are at a distance of the order of the wavelength of the incoming waves. This is classical wave dynamics, nothing quantum to it. The quantum part is that particles are actually waves, and have an associated de Broglie wavelength, which depends inversely on their mass. Presumably, making your objects heavier ...

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The same argument could be said about $w=z\lambda/d$. For any positive $w$ allows solutions $z,\lambda>0$ and $z,\lambda<0$. So if you're looking for the meaning of $\lambda<0$, you are equivalently looking for solutions $z<0$. Given that $z$ is the distance to the screen, I don't think there's any physical meaning. That equation you are using ...

1

If the source is far away, light acquires a certain degree of coherence. Have a look at the Van Cittert–Zernike theorem, also in wikipedia: "the wavefront from an incoherent source will appear mostly coherent at large distances". The resulting fringes are different for different colors, but any color has max for straightforward direction. So, you see the ...

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I'm not sure I can answer your questions about quantum mechanics honestly without equations, but I can tell you something about the details of generating entangled photons with BBO. First, there are two things you need to know about laser light: it has a definite polarization (orientation of the electric field) and definite energy (or, equivalently, a ...

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In order to generate entanglement you need an interaction, by which I mean that the dynamics have a term that is a function of two different degrees of freedom that you intend to entangle$^1$. The type of nonlinearity in this case is what is known as spontaneous parametric downconversion or SPD, which is a nonlinear optical process. 1) How does this ...

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Punk Physicist's answer is spot on. But I'd like to add a little to his/her last two paragraphs, in particular, a description of what it is that you see in an interference pattern. You cannot define a position observable, but you can of course define the state of the second quantized field. Moreover you can describe the probability amplitude for a photon to ...

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There's an old argument by Newton and Wigner, that the photon as a massless particle can't have a position operator and therefore no position space wave function. The paper you're thinking of is T. Newton and E. Wigner, "Localized States for Elementary Systems," Rev. Mod. Phys. 21, 400–406 (1949) doi:10.1103/RevModPhys.21.400. Photons are ...

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The de Broglie wavelength, $\lambda$, is given by $$\lambda = {h \over p}$$ where $h$ is planck's constant and $p$ is momentum. If we take the mass to be $160$ kg and speed to be $100$ ms$^{-1}$ then we get $\lambda = 4\times10^{-38}$m given a slow light spaceship and only one person (more people and speed would increase the momentum and decrease the value ...

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Fundamentally, you can slow down double-slit experiments as much as you like but a version of the Heisenberg principle will not allow you to put definite "gaps" between the detection events or to be sure to produce a photon on demand, at the right frequency etc. It is commonly stated that the particle must be interacting with itself in a double slit ...

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When we look at individual photons, the experiment is about how the individual photons interact with themselves. Since the photon is interfering with itself and not with other photons in the experiment, the interval between the photons does not matter. In a real experiment, however, you have to deal with the fact that your screen is not perfectly isolated ...

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All measurements come from interactions. In our macroscopic world, our intuition is that we can observe things without affecting them, but this is not true at quantum scales. In order for that measurement at the slit to happen, the photon has to interact with something — an electron, say — which couples the state of the photon to the state of the ...

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You are wrong, but understandably so given the ridiculous way in which quantum measurement is commonly discussed. A measurement is an interaction that makes a record of the value of some observable. If such an interaction happens during an interference experiment, the interference doesn't take place. What matters is whether there is a record, not whether ...

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