# Tag Info

3

No, the light rays all travel at the speed of light $c$ but because they travel different distances they arrive at slightly different times. And indeed it is the difference in the light travel time that causes the interference pattern. If we take the phase of the light at the slits as our reference, then the phase change once the light reaches the screen is ...

4

With photons the physical attributes of the pattern are connected to the frequency/energy of the emitted light, which is a wave with wavelength in 400-700nm, right? Yes, with photons the double-slit pattern is not surprising, since photons are excitations of a specific mode of radiation and the modes obey the usual classical wave equation, which of course ...

6

OK you can do it. GP Thomson have done it long before. You need a low pressure vacuum tube to generate the cathode rays (electrons). An essential requirement and rather costly one. I am afraid that you have to make one (size ~500 mm). To do this you need electrocathode (thermionic), resistive heating element, acrylic or glass tube, anode, a rotary vacuum ...

-1

My understanding is that anything that qualifies as an "observation" or "measurement" will cause the "fuzziness" of the superposition to disappear to the local observer, and the results of said experiment will appear in the classical form that we are intuitively used to. The mathematics which controls quantum mechanics describes observed "fuzziness" by ...

1

@Holger Fiedler Hi, Thanks for your comment on my answer here. Here I would like to say that I am an experimental physicist and working on the ultrashort coherent XUV radiation. I have first hand experience with the interference of XUV radiation using double slits. Your question is very genuine. Long ago I have thought over this question for quite a some ...

1

Yes, there is a duality and in the framework of quantum field theory (QFT) it is not even a contradiction at all. It seems pretty natural. All fields and particles are treated very similarly in the QFT language. Both are fields in space-time, so “waves”. There is a suble difference in the spin statistics, namely that fields corresponding to ordinary matter (...

2

Double-Slit Experiment I believe you are describing the double slit experiment with electrons (as opposed to with light). The pattern you are describing is called an interference pattern (much like two pebbles producing ripples in a pond and there are parts where the ripples cancel out). Below is a diagram of the double slit experiment. One way of ...

0

You can always split polarization 2 in two perpendicular directions i.e. parallel to the polarization 1 and perpendicular to the polarization 1. Now the parallel polarization will interfere with each other. You will see fringes of visibility $\frac{I_1-I_2}{I_1+I_2}$. Where intensities can be calculated by relation $I_2=I_1\cos^2\theta$. Other component i.e....

0

An interesting experiment to do if it hasn't been done. The material in the path should slow the photon down in one path more than the other if it's there in different thicknesses. This would shift the interference pattern and demonstrate that the photon went through both slits, so it's not mere ignorance of which slit it went through. As it really never ...

0

It seems like you have established that your photons go through both paths! Not only do you not know which path a photon went through, you know it went through both because of the changes in interference pattern you see. You might want to do this in a controlled way!

4

Get a microscope slide or equivalent thin piece of clear glass. Paint the central portion with india ink or spray with black paint. The coating should be thick enough to prevent the passage of light. Let dry. Using a razor blade and a thin straightedge, scratch a thin line through the paint across the slide (perpendicular to the long direction). As close as ...

0

in order to obtain the wave nature of light you need to make your slits as close to each other as you possibly can as well as make the slits as thin as possible. The two slits/holes need to be VERY close to each other I applaud you for taking interest in experimental physics! Often times experimental physics is a matter of changing all the variables you ...

41

The angle between maxima in the double-slit pattern is $$\theta \approx \frac\lambda d$$ for wavelength $\lambda$ and slit separation $d$. I wild-guess that the slits in your photograph are about 5 cm apart, so your diffraction peaks should be separated by $$\frac\lambda d = \frac{\rm 500\,nm}{\rm50\,mm} = 10^{-5}\rm\,radian$$ which is too small for you ...

-2

I think part of the solution to the conceptual problem is also to recognize that as we make the slits narrower, ever fewer particles actually make it trough. The ideal Gedanken experiment doesn't contain the necessary derivation, it always assumes that all the quanta appear behind the screen. That's not the case in a real experiment, though. The material ...

4

The slit is not of zero width, so there is still considerable uncertainty in the position of the particle. Moreover, the narrowing of the slit does lead to diffraction (i.e. a spread in the momentum).

Top 50 recent answers are included