New answers tagged

2

I'm just guessing here, but one way to interpret it goes like this. If you have the amplitude $\Phi$ for an outcome that can be achieved in multiple indistinguishable ways each described by an amplitude $\phi_i$ with $i \in 1, 2, \dots , n$ we write $$\Phi = \sum_{i=1}^n \phi_i \,.$$ That makes the probability for the outcome \begin{align*} P &= ...


-1

Here is a two slit calculator / simulator I designed in Excel. https://www.dropbox.com/s/kkopfv4xbratc9r/Alsept%20%202%20Slit%20Calculator.xlsx?dl=0 Download,save, open, enable editing The green cells are where you input distance, wavelength, slit width and separation.The yellow cells give you the fringe pattern spacing. The graph represents the right half ...


0

Calculate the Fraunhofer diffraction integral of your slits and take the absolute square to get intensities.


0

Imagine a billiard ball as it rolls on the flat billiard board in a straight line with constant velocity as expected. Then suddenly it changes direction. What happened? As you may think the billiard ball is not alone, there are other balls that collided with it. That's same situation with the wave function collapse. We are dealing with a partial system not ...


4

As a diagram screen $A$ is closer than screen $B$ and so the fringes are closer on screen $A$: Fringe separation $\Delta x = \dfrac {\lambda \; D}{d}$ where $d$ is the slit separation, $\lambda$ is the wavelength of light and $D$ the distance from the slits to the screen.


0

In the many world interpretation of quantum mechanics, there is only a split into different branches when decoherence takes place. So there would be no split in the two slit experiment until the photon hits the photographic plate. At that stage decoherence takes place and there would be a split into a separate Universe (branch) each of which has the photon ...


3

Firstly, I find the hostility against many worlds interpretation inadequate. As far as understanding quantum mechanics goes, the case is far from closed. I believe that it is unlikely, that this question will be answered near future (and it is plausible that it will be never resolved). Nevertheless, something being inherently hard should not suppress our ...


3

As stated by Luboš Motl in another answer, there is no consensus between Everett's interpretation contenders about what it means exactly. The common idea is that no state evolution other than unitary as per Schrödinger should be accepted (no collapse) but that's about it. Indeed it is not clear at all what is supposed to be splitting or branching, and when. ...


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The answer should be zero since each source is emitting light of same wavelength and same intensity thus same amplitude. The path difference between $S_4$ and $S_3$ is 10.5$\lambda$ thus their phase differnce is π and hence they interfere destructively giving 0 amplitude. Same is the case for source $S_2$ and $S_1$ which gives zero amplitude. Now net ...


0

The first thing you need to do is make an assumption about the relative phase of the waves emitted by each source which with no other information you make zero. Then you need to add the amplitudes from all four sources taking account of the relative phase due to the distances the waves have travelled and then square the result to get the intensity.


-2

Nothing about light traveling through a slit or opening actually makes spatially incoherent light become coherent. What occurs is that, where you have an incoherent light-source, i.e. a non-point or extended source, and you place in its path a small enough opening, you're isolating light that was emitted, relatively speaking, from a single point on that ...


0

"Thomas Young used a single slit between the light source and the double slits. I can't understand why did he used the single slit, since the light from only one source is coherent already or isn't it? Does the narrow single slit make incoherent source coherent?" This answer is not to imply that Anna V's is incorrect. One of the sources of confusion when ...


0

The Many Worlds Interpretation is a theory of non relativistic quantum mechanics where there is a wavefunction from the configuration space of the entire system (and this is utterly essential) into the joint spin state of the entire system and it evolves according to the Schrödinger equation, and nothing else. No one claims (or has ever claimed) that in one ...


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There doesn't exist any "totally well-defined" realization of MWI but its champions want to agree with the basic experimental facts so they would almost certainly say that there is no splitting of the worlds when a particle goes through two slits. Instead, if there's any splitting of the worlds at all, and different MWI advocates have different opinions ...


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Each of the two edges of a slit act as point sources and all light coming from them is coherent. This can easily be proven mathematically. Each edge forms a single edge fringe pattern on the screen with alternating dark and light fringes calculated as m=the square root of wavelength times distance times (m+3/4) where m = the number of spaces out from the ...


2

As strange as it may be to hear, the double-slit experiment conducted one photon at-a-time with "detectors at the slits" is nothing short of a myth. No such experiment has been reported in a peer-reviewed journal or any reputable book or publication. Talk of this supposed experiment, and even figures illustrating it, can be found throughout the internet, but ...


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Quantum mechanics is a theory that can only predict probability distributions. It cannot predict trajectories. It is ruled by differential equations which have as solutions the wavefunctions, and the complex conjugate square of the wavefunction gives the probability of a specific, photon, electron, to be at (x,y,z,t) given the boundary conditions of the ...


1

According to quantum physics, when certain different polarizers are placed over the slits in the double-slit experiment (for instance, one vertical and one horizontal polarizer, or one circular clockwise and one circular counter-clockwise), thus "marking" each photon with which-way information, the photon indeed passes through only one slit, resulting in no ...


0

Any measurement you make at the slits is going to destroy the interference pattern. The wavefunction of the photon or electron collapses as soon at it interacts with the environment in a thermodynamically irreversible way. In essence, any type of measurement you could make that would tell you which slit a particle went through would cause the wave function ...


-4

You can't detect single photons. There is no way to prove that a click in a photodetector represents a single photon versus the response of the system to an electromagnetic wave. There is no way to prove that the appearance of a fleck of silver on a photographic plate represents a single photon versus the response of the silver bromide crystal to an ...


0

It is just a misleading concept that electron is particle or a wave ... the answer is neither particle nor wave but BOTH. How we came to know that electron is particle?? Suerly through experimental evidences. A man is affected by its very imediate surroundings .. and what is in surroundings .... ?? Most oftenly matter. Electron is particle or a wave is ...


0

If we setup the camera to record like above but NEVER EVER EVER look at the result of what was recorded. Does the wave function still collapse? The answer is that we just don't know. We can tell that the wave function has collapsed (in Copenhagen terms) only when we humans look at the system -- in the canonical experiment that means looking at the ...


1

You can find an extensive treatment of the double-slit experiment with electrons in Feynman Path Integral approach to electron diffraction for one and two slits, analytical results (Beau, 2012). The paper discusses both Fraunhofer and Fresnel regimes. These regimes do hold for electrons. Interestingly it does not use the standard semi-classical ...


0

The very word, photon, belongs to the quantum mechanical regime. It is one of the elementary particles in the standard model of particle physics. Elementary particles are described with quantum mechanical wave functions, which are complex function. The complex conjugate square gives the probability of finding the particle at (x,y,z,t). In the case of the ...


0

It has to do with the total energy or power of the EM wave you're interested in, as well as the frequency of the wave. As a simple example, a 3mW laser at 500nm wavelength will produce roughly 7.55*10^15 photons per second. From how large this number is, it's not difficult to see how light will usually be made up of an extremely large number of photons. For ...


3

In quantum mechanical domain these type of question does not have meaning. Every single photon is associated with a wave and vice versa. But to talk whether an electromagnetic wave contains a single photon or not is an ambiguous statement. When people say an electromagnetic wave necessarily contains many photons it only means that a incident beam of ...


0

That electrons diffract according to the de Broglie wavelength was confirmed back in 1925, the Davisson-Germer experiment. Davisson attended the Oxford meeting of the British Association for the Advancement of Science in the summer of 1926. At this meeting, he learned of the recent advances in quantum mechanics. To Davisson's surprise, Max Born gave a ...


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Diffraction has two regimes: Fraunhofer diffraction and Fresnel diffraction. The Young's slit experiment is governed by Fraunhofer diffraction , where the diffraction pattern is simply the Fourier Transform of the aperture function; for a double-slit aperture the aperture function is a double 'top-hat' function; and the Fourier Transform of this is a cosine ...



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