Why do particles act like waves

In summary, the top theories as to why particles show the interference pattern in the double slit experiment revolve around the concept of particle-wave duality. Quantum field theory is the most widely accepted explanation for this phenomenon, but there are also other theories such as the path integral formulation. However, the question of why particles behave in this manner remains unanswered and is a topic of ongoing debate and research.
  • #1
Pjpic
235
1
What are the top theories as to why particles show the interference pattern in the double slit experiment.
 
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  • #2
The particle-wave duality is 'explained' in quantum field theory.
 
  • #3
Pjpic said:
What are the top theories as to why particles show the interference pattern in the double slit experiment.

Particles do not act like waves, and wave do not act like particles.
Only very narrow "wave packets" act like particles
 
  • #4
malawi_glenn said:
The particle-wave duality is 'explained' in quantum field theory.

I see that the behavior of particles is described using waves, but I'm not finding where the 'why' is discussed.
 
  • #5
Pjpic said:
I see that the behavior of particles is described using waves, but I'm not finding where the 'why' is discussed.

I said Quantum FIELD theory
 
  • #6
malawi_glenn said:
I said Quantum FIELD theory

But how Quantum FIELD theory "explain it"?
 
  • #7
feynmann said:
But how Quantum FIELD theory "explain it"?

The question was WHICH theory, not how ;-)

http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WB1-48CFHST-1-5W&_cdi=6697&_user=651519&_orig=search&_coverDate=06%2F30%2F2003&_sk=996949997&view=c&wchp=dGLzVzz-zSkWA&md5=8059eb26e8bb672bc86d8bc20684c63e&ie=/sdarticle.pdf

http://www.physnet.org/modules/pdf_modules/m246.pdf

There should probably exist good articles on American Journal of Physics.
 
  • #8
The interference picture, consisting of "points", shows probabilistic space distribution. A particle is understood as a point solely so it is not possible to explain interference effects with (classical) "particle" theory. At the same time, waves fill the whole available space, not only one point in it. So the waves are used to describe the spatial spread of interference picture. Of course, they are not usual waves but waves of amplitude of probability. It is the experimental facts that lead to this (QM) picture.

Bob.
 
  • #9
The explanation is unfortunately that particles as such do not exist. You will have to get rid of your concept of reality, which no one gives up without a fight. For quantum mechanics to work particles must exist in a "quantum state" in between measurements where they don't have exact positions, or speeds. This is all very well established classic quantum mechanics. There is pretty much just one theory about this and all the fancy other theories like quantum field theory, Bohmian mechanics, and even string theory (if it ever gets there) are build such that this theory is reproduced.
The main problem is interpretation, the question is still open how much reality we can get back into the picture. Can we call the wavefuncion real? Does it collapse at a measurement?
No one knows, and if you have a book that tells you it does, throw it away please.
 
  • #10
Pjpic said:
What are the top theories as to why particles show the interference pattern in the double slit experiment.

I have to agree with malawi_glenn in this instance, that QFT is the best description, in that it predicts the interference pattern given the energies of the particles involved.

As to *why* they interfere, no-one knows. But no-one knows why objects fall to the ground when left to their own devices. We can explain it well with theory and even predict quite a lot about *how* they will behave. But not why.

In this specific instance, I think you'll be looking at the path integral formulation. I'm not sure what your level of maths is, but if you don't know what a functional integral is, look up the Douglas Robb memorial lectures where a clever guy gave an overview of QED for the layperson. It's really quite easy to follow and doesn't mislead at all to my knowledge. Anything you learn will not have to be unlearned later.
 
  • #11
These type of why questions aren't really answerable. It's the same as asking 'Why are there electrons?'. In the abscence of available answers, think about it and reach your own conclusion.
 

1. Why do particles sometimes exhibit wave-like behavior?

Particles, such as electrons and photons, can exhibit wave-like behavior due to their quantum nature. According to the principles of quantum mechanics, particles do not have definite positions or velocities, but rather exist in a state of superposition where they can behave as both a particle and a wave simultaneously.

2. How can a single particle be in multiple places at once?

This is known as the wave-particle duality and is a fundamental property of quantum particles. The wave-like behavior of particles allows them to exist in multiple states simultaneously, until they are observed or measured. This concept is known as the collapse of the wave function.

3. What causes particles to behave as waves?

The behavior of particles as waves is a result of their inherent energy and momentum. When particles are in motion, they create a wave-like disturbance in the surrounding space, known as a wave function. This wave function describes the probability of finding the particle at a particular location.

4. Can all particles behave as waves?

Yes, all particles have wave-like properties, but the extent to which they exhibit these properties depends on their mass and speed. The de Broglie wavelength, which describes the wave-like behavior of a particle, is inversely proportional to its mass and directly proportional to its velocity. Therefore, larger and slower particles have a shorter wavelength and exhibit less wave-like behavior compared to smaller and faster particles.

5. How do we know that particles act like waves?

The wave-like behavior of particles has been observed through various experiments, such as the double-slit experiment. In this experiment, particles, such as electrons, are fired through two parallel slits and create an interference pattern on a screen behind the slits, similar to how waves behave when passing through two slits. This and other experiments have provided evidence for the wave-particle duality of particles.

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