Conditions for Double-Slit Interference in Quantum Mechanics

In summary, during a conversation with a friend, they asked questions regarding the interpretation and conditions for double-slit interference in relation to light and photons. Both parties had not personally tested the experiment and had only read about it in books. The friend argued that in quantum mechanics, the conditions for the interference do not matter, while the speaker believes that they are still relevant. The speaker also questions if the same conditions apply when using electrons in the experiment.
  • #1
Robert_G
36
0
Hi, there

Today, a friend came to me and asked the following questions and they made me confused.
If the source is strong, the light has to be considered as wave, and the double-slit interference (DSI) can be interpreted, and the conditions for the DSI is (1) same frequencies, (2) parallel polarization, and (3) constant phase differences.

If the source is week, one photon after one photon, for example. DSI will give us spots at the beginning; but give it a long time, the pattern will be formed.

Both of us never check it in the laboratory, we just read it from the book. However, In the "Quantum Mechanics" books, the above three conditions never be mentioned, As if those conditions does not mattered anymore.

In my opinion, All the three conditions are still needed. The character of frequency, polarization and phase difference are still with photons. Just look at the formulas of the creation and annihilation operators for the field. However, I can explain what the frequency, polarization and phase difference means to the particles (photons here), So I can not convince him, and my dear friend insists that those three conditions fade away in Quantum mechanics.

If we use the electrons in the DSI experiment, the coherent source is still need, right?

So, what you think?
 
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  • #2
Dear me, I put my questions in the wrong place, here is classical physics, what should i do?
 

1. What is the double-slit experiment?

The double-slit experiment is a classic experiment in quantum mechanics that demonstrates the wave-particle duality of light and matter. It involves shining a beam of particles, such as electrons or photons, through two narrow slits and observing the resulting interference pattern on a screen.

2. How does the double-slit experiment demonstrate quantum mechanics?

The double-slit experiment shows that particles can behave like waves, as they create an interference pattern on the screen. This phenomenon is only explained by the wave-like nature of particles in quantum mechanics.

3. What are the conditions necessary for double-slit interference to occur?

The conditions for double-slit interference include having a coherent source of particles, such as a laser, and two narrow slits that are close enough together to create an interference pattern. The particles must also be small enough to exhibit wave-like behavior.

4. How does changing the distance between the slits affect the interference pattern?

Changing the distance between the slits affects the interference pattern by altering the wavelength and thus the spacing of the interference fringes. As the distance between the slits increases, the interference pattern becomes wider and the fringes become more spaced out.

5. What happens to the interference pattern when only one slit is open?

When only one slit is open, the interference pattern disappears and a single-slit diffraction pattern is observed. This is because there is only one source of waves, so there is no interference occurring between the two slits. This further supports the wave-like behavior of particles in quantum mechanics.

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