De Broglie wavelength - model for comparing photons and electrons

In summary, the conversation discusses the differences between the wavelength of a freely propagating photon and a freely propagating electron. While the classical picture of oscillating electric and magnetic fields can be used to determine the wavelength of a photon, the quantum picture of an oscillating probability function is needed for an electron. However, neither approach is fully adequate and a more comprehensive understanding may require the use of quantum field theory. The question also raises the possibility of a semi-classical model that can accurately describe both particles and the concept of de Broglie wavelength.
  • #1
HJ Farnsworth
128
1
Hello,

I'm thinking about the wavelength of a freely propagating photon vs. a freely propagating electron.

For the photon, we have the classical picture of oscillating [itex]E[/itex] and [itex]B[/itex] fields perpendicular to the direction of propagation, and we call the wavelength of the photon, which can be identified as its de Broglie wavelength, as the length between successive crests of either of those fields.

For an electron, we can use the simple quantum picture of an oscillating probability function, and we can identify the de Broglie wavelength as the length between successive crests of the probability field.

As far as I know there is no transverse oscillating EM field associated with a freely propagating electron, and the Schrodinger equation is inadequate to analyze the wavefunction of a photon - so, the classical picture of the dB wavelength fails for the electron, and the quantum picture fails for the photon.

Probably something like QFT is needed to really understand what is going on, but does anyone know of a model or a conceptual picture that makes sense for a direct comparison for the wavelengths of electrons or photons that doesn't require jumping between two theories? For instance, can a freely propagating electron be modeled as an oscillating EM field in the same manner as a photon (this doesn't seem correct to me, but I'm wanting to give an idea of the kind of thig I'm looking for)? Similarly, can we picture the photon as a propagating probability oscillation (or more what I'm looking for, if so how does this then lead to the classical oscillating EM fields)? Or is there a good semi-classical model that fits both well, and reveals some interesting stuff as a result/gives a good intuition of why the concept of a dB wavelength is applicable to both photons and electrons as a result?

Thanks very much.
 
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Related to De Broglie wavelength - model for comparing photons and electrons

1. What is the De Broglie wavelength?

The De Broglie wavelength is a physical concept that describes the wave-like nature of matter, in particular, photons and electrons. It was proposed by French physicist Louis de Broglie in 1924 as a way to compare the behavior of particles to that of waves.

2. How is the De Broglie wavelength calculated?

The De Broglie wavelength can be calculated using the equation λ = h/mv, where λ is the wavelength, h is Planck's constant, m is the mass of the particle, and v is its velocity. This equation shows that the wavelength is inversely proportional to the momentum of the particle.

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

The De Broglie wavelength allows us to understand the behavior of particles at the quantum level. It showed that particles, such as electrons, behave both as particles and waves, and their wave-like properties can be observed in their interference patterns. This concept played a crucial role in the development of quantum mechanics.

4. How does the De Broglie wavelength model compare photons and electrons?

The De Broglie wavelength model allows us to compare photons and electrons by considering them both as waves. While photons have a constant velocity of light, their wavelength is inversely proportional to their energy. On the other hand, the velocity and wavelength of electrons can vary depending on their energy.

5. What are the limitations of the De Broglie wavelength model?

The De Broglie wavelength model is not applicable to large objects, as their wavelengths would be too small to be observed. Additionally, it does not fully explain the behavior of particles at the quantum level, and further research and theories, such as wave-particle duality, are needed to understand the complex nature of matter.

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