De Broglie wavelength and velocity

In summary, DeBroglie developed a theory about the shorter wavelength of objects moving faster before relativity was developed. DeBroglie's theory is still a non-relativistic theory, even though it incorporates relativistic momentum.
  • #1
durant35
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I was wondering about the equation for the de Broglie wavelength which indicates that the wavelength of any object is shorter when the object is moving faster. Why does this occur? And how we connect this with special relativity where the velocity depends on the frame of reference.
 
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  • #2
The wavelength is shorter because the momentum is higher. De Broglie was developed before SR, so it is not a relativistic theory.
 
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  • #3
durant35 said:
And how we connect this with special relativity where the velocity depends on the frame of reference.

The wavelength also depends on the frame of reference. Note that velocity and wavelength depend on the frame of reference, even in non-relativistic mechanics.
 
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  • #4
Doc Al pointed out that I was wrong about the sequence of events - DeBroglie was after SR. However, it is still a non-relativistic theory.
 
  • #5
Vanadium 50 said:
Doc Al pointed out that I was wrong about the sequence of events - DeBroglie was after SR. However, it is still a non-relativistic theory.
I'm sorry, but de Broglie's thesis from 1924 starts from ##E = mc^2##. It is then by combining this with Planck's ##E = h \nu## that he ends up with a wavelength for a matter wave. I don't see how this is not a relativistic theory.

A reproduction of the thesis (in French) can be found at https://tel.archives-ouvertes.fr/tel-00006807/en/
 
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  • #8
DrClaude said:
That link doesn't work.
Hm. Works here. What kind of error do you get?
 
  • #9
DeBroglie essentially takes a fundamentally NR equation and stick in the relativistic expression for momentum in it. That doesn't make it a relativistic equation. (If it did, GR would have been invented a decade earlier.) As pointed out earlier, it doesn't transform right. In modern language, it takes one component of a 4-vector and relates it to three components of a different 4-vector.
 
  • #10
Heinera said:
Hm. Works here. What kind of error do you get?
Server not found.
 
  • #11
DrClaude said:
Server not found.
Ok. See if you have better luck with this server:

http://www.plasma.uaic.ro/topala/articole/De_Broglie%201927.pdf
 
  • #12
Heinera said:
Ok. See if you have better luck with this server:

http://www.plasma.uaic.ro/topala/articole/De_Broglie%201927.pdf
Yes, it works.
 

1. What is the De Broglie wavelength?

The De Broglie wavelength is a concept in quantum mechanics that describes the wavelength associated with a moving particle. It is given by the equation λ = h/mv, where h is Planck's constant, m is the mass of the particle, and v is its velocity.

2. How is the De Broglie wavelength related to the velocity of a particle?

The De Broglie wavelength is inversely proportional to the velocity of a particle. This means that as the velocity increases, the wavelength decreases and vice versa.

3. What is the significance of the De Broglie wavelength?

The De Broglie wavelength is significant because it shows that particles, such as electrons, have both wave-like and particle-like properties. This phenomenon is known as wave-particle duality and is a fundamental concept in quantum mechanics.

4. Can the De Broglie wavelength be observed in everyday objects?

No, the De Broglie wavelength is only significant for particles with very small masses, such as electrons, protons, and neutrons. The wavelength of larger objects, such as humans or cars, would be too small to be observed.

5. How does the De Broglie wavelength affect the behavior of particles?

The De Broglie wavelength affects the behavior of particles in various ways. It explains phenomena such as diffraction and interference, where particles exhibit wave-like behaviors. It also plays a role in the uncertainty principle, which states that the more precisely we know a particle's position, the less we know about its momentum, and vice versa.

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