Feymman's theory, double slit experiment - Stephen Hawking

In summary: Single_photons_cannot_interfere_with_each_other2. As the particles have already passed by the slits, it should have already suffered interference, so why isn't there fringes anymore?SW explains John Wheeler experiment, where we take the picture only a moment before it collides with the screen.In summary, Stephen Hawking explains that single particles can have interference by themselves and that in the double slit experiment, if we try to take a picture of the particle at the moment it pass by the slit, to see in which slit it passes by, the interference disappears. This is explainable without time reversal.
  • #1
jaumzaum
434
33
Hi all,

I was studying Stephen Hawking's new book (very good, by the way). He was explainning Feymann's theory, that says a particle travels by all the ways possible to reach a given point. So single particles CAN have interference by themselves. Then he explain why, in the double slit experiment, if we try to take a picture of the particle at the moment it pass by the slit, to see in which slit it passes by, the interference disappears. SW says we change medium and its possible past(??) as we take a picture, and by far as I've understood, we change the medium because the photons collide with the particles, and changes its direction.

1. The first question is about this. I can't see why a single photon preclude all the other Freymann's trajectories the particle could have. Especially if they are big particles as fulerens.

And then SW explains John Wheeler experiment, where we take the picture only a moment before it collides with the screen.

2. As the particles have already passed by the slits, it should have already suffered interference, so why isn't there fringes anymore?

Thank you all by this exellent forum that helped me a lot!
And I'm really sorry if you notice some mistakes in my english. I'm brazilian :\

[]'s
John
 
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  • #2
Nobody?
 
  • #3
jaumzaum said:
SW says we change medium and its possible past(??) as we take a picture, and by far as I've understood, we change the medium because the photons collide with the particles, and changes its direction.

There is no need for time reversal, it is explainable without that.

jaumzaum said:
1. The first question is about this. I can't see why a single photon preclude all the other Freymann's trajectories the particle could have. Especially if they are big particles as fulerens.

No one knows but there are various interpretations on/about that.

http://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics
 

1. What is Feynman's theory?

Feynman's theory, also known as the Feynman path integral, is a mathematical formulation of quantum mechanics. It describes the behavior of subatomic particles and their interactions using a combination of classical and quantum principles.

2. What is the double slit experiment?

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

3. How does Feynman's theory explain the results of the double slit experiment?

Feynman's theory provides a mathematical framework for understanding the behavior of particles in the double slit experiment. It explains that particles have a probability of behaving like waves, with multiple possible paths and outcomes, and that the interference pattern observed on the screen is a result of these probabilities.

4. What is Stephen Hawking's contribution to Feynman's theory and the double slit experiment?

Stephen Hawking, a famous physicist and cosmologist, used Feynman's theory to explore the concept of quantum tunneling, where particles can seemingly pass through barriers that they shouldn't be able to cross. He also discussed the implications of Feynman's theory for the concept of time and the arrow of time.

5. How has Feynman's theory and the double slit experiment impacted our understanding of the universe?

Feynman's theory and the double slit experiment have greatly impacted our understanding of the quantum world and have challenged our traditional understanding of the universe. They have helped us develop technologies such as transistors and lasers, and have opened up new areas of research in quantum computing and quantum information theory.

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