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90
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7answers
7k views

Stupid yet tricky question: Why do we actually see the sun?

I haven't yet gotten a good answer to this: If you have two rays of light of the same wavelength and polarization (just to make it simple for now, but it easily generalizes to any range and all ...
0
votes
0answers
90 views

3D interference visualisation software

We are searching for a software program that simply helps us to visualize in 3D the interference of planar waves of multiple sources (frequencies) and as sepctrum on a wall. Something like a well ...
8
votes
7answers
2k views

A Musical Pathway

Using a small number of sound emitters, could you create a room where certain nodes emitted particular tones, but no meaningful sound was heard anywhere else. So, for example, by walking down a ...
2
votes
3answers
221 views

Can random constructive interference with sound waves cause damage?

Any two sound waves have a random chance to constructively interfere with each other at a given spot and this will cause an increase or decrease in pressure. So is it possible that a large number of ...
2
votes
1answer
290 views

Young's Double slit experiment (Finding the value for slit separation) [closed]

The question illustrates mono-chromatic red light passing through 2 slits and forming an interference pattern on the screen. The question then asks to suggest a suitable value for the slit separation. ...
1
vote
0answers
72 views

Salisbury Screens and Energy Conservation

From Wikipedia on how a Salisbury Screen works: 1. When the radar wave strikes the front surface of the dielectric, it is split into two waves. 2. One wave is reflected from the glossy ...
4
votes
3answers
1k views

Do laser beams interfere noticeably with each other?

I want to arrange some red lasers along a 90 degree arc of a circle, aimed towards the center of the circle. When their beams hit the opposite side of the circle, will I notice any interference ...
-1
votes
1answer
51 views

What is the equation for condition of obtaining a bright spot in a wedge shaped film?

I want to know if the condition for obtaining a bright spot in a wedge shaped film is $2 \mu t\cos(r+\theta)=(n+\frac{1}{2})λ$ or $2 \mu t \cos(r+\theta)=(2n-1)λ/2$ . $t$ = thickness $r$ = angle ...
2
votes
0answers
65 views

What is three-photon interference?

Whilst reading this paper on a quantum processor that performs a type of matrix computation, I came across the concept of 'three-photon interference'. A quick Google search shows that this process is ...
0
votes
1answer
101 views

EM Waves Energy Loss

Where does the energy go when two photons interfere destructively at a point on a screen in Young's double slit experiment ?
0
votes
0answers
99 views

The interference of waves and factors that affect cancellation?

If you had two repeated disturbances on the surface of a water, I know interference will occur. However, if I move the two sources of disturbances closer together, why would the 'gaps' between each ...
1
vote
1answer
289 views

Can we use intensities in the superposition principle?

In using the superposition principle to calculate intensities in interference patterns, can we add the intensities of the waves instead of their amplitudes? I think that amplitude account for the ...
3
votes
1answer
386 views

Single photon interference experiment

In short: the question is, does the length of the path affect the outcome of detecting a photon? Consider the single photon beam splitter experiment. Does the probability of detecting the photon ...
8
votes
2answers
3k views

Where does energy go in destructive interference? [duplicate]

I have read that when two light waves interfere destructively, the energy contained within is transferred to other parts of the wave which have interfered constructively. However, I am having some ...
2
votes
1answer
2k views

How to calculate the intensity of the interference of two waves in a given point? [closed]

There are two different point sources which produce spherical waves with the same power, amplitude, ω, wavenumber and phase. I can calculate the intensity of each wave in a point: $$ I_1 = P / (4 ...
2
votes
0answers
141 views

How to make DIY flight detector for double slit experiment?

I want to reproduce double slit experiment. So, is it possible to build flight detector (situated near one slit) at home? Is it possible to buy it somewhere?
0
votes
1answer
139 views

Young experiment: square of classical real wave function

I can't understand why the sum of two real waves result in a time dependent wave, but not so for the complex waves. In details, I can't get this passage on p.38-39 in A.C. Phillips, Introduction to ...
0
votes
3answers
132 views

How do I determine where I can no longer hear sound?

A teacher stands well back from an outside doorway that is 95 cm wide and blows a frequency of 600 Hz. The door faces north. Assume the speed of sound is 340 m/s and that there are no reflections. At ...
1
vote
1answer
258 views

Kiessig fringes

I have come across many papers but still couldn't find the relationship between index of refraction or atomic scattering factors, and reflectivity. My flow of thought goes as follows: Get the ...
1
vote
2answers
481 views

Double slit experiment alternating holes

If we perform the double slit experiment by shoting photons covering one hole at a time, would we see equally the double slit interference?. That is, the same set up of double slit but fire photons ...
3
votes
2answers
214 views

Probability wave speed of dispersion and interference

I'm a layperson learning about quantum mechanics and probability waves. My understanding is that the probability wave for the position of a particle disperses throughout all of the universe. I have ...
2
votes
0answers
146 views

photon and Z boson interference?

I'm not certain that this question will make sense, but here goes... In most monte carlo generators, when Z events are produced, there is a lower mass cutoff on the Z pole. I've been told that this ...
2
votes
1answer
243 views

Considering the wave function is not 'real', what is interfering?

I find the idea of the wave function being 'just' a collection of numbers (probabilities) quite alluring, and elegant in explaining away the whole 'collapse' business (see Luboš' answer to this ...
2
votes
4answers
1k views

Single photon and double-slit experiment [duplicate]

Laser fires single particles of light, called photons, through the slits. Even though only single photons of light are being fired through the slits and They create three pattern again. How single ...
1
vote
2answers
342 views

Interference, photon's phase, and the Hilbert space

Dirac said that a photon can only interfere with itself. This is consistent with the tensor product of two photon spaces representation. On the other hand, it is known that there is interference ...
6
votes
3answers
188 views

supressing certain decay paths and enhancing others with interference

In a scattering reaction, there are many possible final states for the products, each with different production rates. Question: Is there a way in which we could in general supress certain rates ...
6
votes
3answers
618 views

Triple slit experiment

If the experiment is done with single photons and a "detector" at one of the slits the interference pattern breaks down. What happens if three slits are used with single photons and a "detector" at, ...
2
votes
2answers
311 views

A question on intereference experiment with water waves as given in the Feynman Lectures on Physics

I have a question related to the interference (thought)experiment with water waves given in the book Feynman Lectures on Physics Vol.3. When only one hole (hole 1) is open the measured wave intensity ...
1
vote
1answer
2k views

Light interference maximum and minimum intensity points

This is a very basic question, but I just forgot how to solve this. It's classical physics question. Suppose that there are two light sources. And some place away exists a screen. How do I find ...
1
vote
2answers
536 views

Can electrons change the frequency of light as they bounce off/around?

I know that light does not interact with other light, but can interfere it, at least its amplitude. With that said, lights frequency can be changed via bouncing off matter, where matter might absorb ...
1
vote
1answer
567 views

How Light or Water Intensity is equal to square modulus of wave function of Light or Water Waves $I=|\psi|^2 \,$?

I've seen the Wave Function as a psi $\Psi$ $\psi$. And always heard that the wave function is the Complex Number as Imaginary and real number. But I've never seen it I've never seen components of ...
3
votes
1answer
77 views

Describing quantum intereference with only currents and densities

I know about and believe to understand the general wave equation based Kirchhoff diffraction formula, which in the Fraunhofer limit leads to a farfield complex wave function by Fourier transforming ...
39
votes
11answers
9k views

What happens to the energy when waves perfectly cancel each other?

What happens to the energy when waves perfectly cancel each other (destructive interference)? It appears that the energy "disappear" but the law of conservation of energy states that it can't be ...
4
votes
3answers
400 views

Which is the biggest object which can interfere with itself?

I've heard that scientist proof that viruses of the Tobacco mosaic virus could interfere with themselves. I'm referring to quantum interference-- the same as photons. Unfortunately, I couldn't find ...
6
votes
1answer
324 views

Are two polarization states of light coherent?

Let's consider a situation: we have distant point source of unpolarized light in certain non-zero range of wavelengths (it's polychromatic). Let's divide this light into 2 beams depending on ...
4
votes
2answers
174 views

What are the lines visible between two cards held edge-to-edge?

Hold two cards (say credit cards) edge to edge, anything from a very slight touch to about 1/3 mm separation, in front of any ordinary light source. When I do this I see several fine dark parallel ...
4
votes
4answers
1k views

Young's double-slit experiment with detectors

Related: Accuracy of various optical instruments In many books, it's written that knowing which slit a photon passes through (by placing a detector before the slit) in a Young's double-slit setup ...
3
votes
1answer
2k views

Purple doesn't occur in rainbow - or does it?

Usually, when asked whether the purple color exists rainbows, an answer similar to this is given: The purple color is perceived by human eyes via the activation of both red-sensitive and ...
2
votes
3answers
681 views

What does the differential of $d_s\sin(\theta) = m\lambda$ help us see, with respect to waves through diffraction gratings?

With respect to waves traveling through a diffraction grating, we have an equation like this one: $$d_s\sin(\theta) = m\lambda.$$ Where $d_s$ is the distance between slits in the grating, $\theta$ is ...
4
votes
3answers
1k views

Why does light in a room not form constructive and destructive interference patterns?

This is something that I have wondered for a long time. How come when I walk around why do I not see random black spots where light has collided destructively and bright spots where it has collided ...
2
votes
1answer
579 views

Why do I hear beats through headphones only at low frequencies?

I was recently playing with this Wolfram Demonstrations applet, which demonstrates beats. At first I thought the app didn't work because I couldn't hear any beats. Then I realized that the applet ...
5
votes
2answers
305 views

Two paths having the same phase in the path integral approach

In the path integral approach to Quantum Mechanics, can two distinctly different paths of the possible infinite paths have the same phase, i.e can there be a bimodal distribution of the phases ...
11
votes
6answers
2k views

How come an anti-reflective coating makes glass *more* transparent?

The book I'm reading about optics says that an anti-reflective film applied on glass* makes the glass more transparent, because the air→film and film→glass reflected waves (originated from a paraxial ...
7
votes
3answers
2k views

Why don't waves with different wavelengths interfere with each other in white-light?

The book I'm reading about optics says at some point that "each color (wavelength) contained in the white light interferes only with itself". But why is this so? Edit: I moved the rest of the ...
0
votes
2answers
738 views

Wave diffraction explanation

I'm trying to understand wave diffraction and I found this wikipedia article. It's in Czech so I'll explain a bit. I'm interested in the 4 images I couldn't find on english wikipedia. The first one is ...
5
votes
3answers
684 views

Recently publicized experiment on destructive interference between two laser beams

Recently I've had several non-physicist friends ask me, independently of each other, about an experiment where two collinear laser beams destructively interfere along a certain length. Everybody wants ...
14
votes
4answers
2k views

Energy conservation and interference

I have a problem with energy conservation in case of interfering waves. Imagine two harmonic waves with amplitudes $A$. They both carry energy that is proportional to $A^2$, so the total energy is ...
1
vote
1answer
360 views

Double-slit experiment with alternating on-off switch

Suppose we perform a double-slit experiment with a detector placed at a position of minimum intensity (maximum destructive interference), off-center where the path lengths differ by half a wavelength. ...
1
vote
2answers
248 views

Double slit experiment and perforated walls' properties

I have a doubt about how double slit experiment is made. Let's think about the perforated wall, what are the requirement for it? Can a photographic plate could be used as a wall ? I see a problem ...
1
vote
2answers
327 views

What's inside the slit in double slit experiment?

If double slit experiment is done in a environment with air, then slits could also contain air made up of (approx. 80% nitrogen, 20% oxygen), then there is not empty space inside the slit. How can it ...