The electron as a wave: what is it that waves

  • Context: Graduate 
  • Thread starter Thread starter carwe
  • Start date Start date
  • Tags Tags
    Electron Wave Waves
Click For Summary

Discussion Overview

The discussion centers on the nature of the electron when described as a wave, particularly what aspect of the electron is oscillating and how this relates to concepts of probability and quantum mechanics. Participants explore the implications of wave-particle duality and the mathematical interpretations of quantum states.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions what kind of wave the electron behaves as, suggesting it might be a probability wave, which is affirmed by a lecturer.
  • Another participant clarifies that it is the quantum phase that waves, not the probability itself, which can remain constant while the phase varies.
  • There is a distinction made between the electron field and the electromagnetic field, with a suggestion that fermion fields differ from boson fields.
  • A participant argues that a photon cannot be described as a probability wave, presenting this as a flaw in quantum mechanics.
  • Another participant emphasizes that the "waves" are mathematical constructs used to describe quantum states, with physical interpretations derived from the absolute square of wave functions.
  • Experiments are cited where electrons exhibit wave-like behavior, such as producing interference patterns when shot at a crystal.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the waves associated with electrons and photons, with no consensus reached on whether probability waves are a valid description. The discussion remains unresolved regarding the interpretation of these concepts.

Contextual Notes

Limitations include the dependence on definitions of wave functions and quantum states, as well as unresolved interpretations of the mathematical constructs involved in quantum mechanics.

carwe
Messages
2
Reaction score
0
The electron as a wave: what is it that "waves"

When taking a course in Modern Physics, after doing quite a lot of thinking, I finally asked the lecturer: when the elctron behaves as a wave, what kind of wave does it behave as? Does it behave as an electromagnetic wave? The answer was no. I thought for a second an asked, "Is it the probability that waves"? The lecturer thought for some moments and then aswered "yes".

Or, in other words, my question is: what does the oscillating variable describe? For an em wave it is obvious, it is the magnitude of the electric or magnetic field. So, when describing the electron as a wave, is it still so?

No, acording to the lecturer, which makes sense; we e.g. calculated the wave function for an electron-in-a-box, clearly; the wave appears and it is apparently the probability that "waves".

...but, in that case: when an em wave behaves as a particle, a photon, can that photon also be described as a "probability wave", different from the em wave?

Can someone give me some hints on this? I might very well be messing up a lot of things...

Thanks.
 
Physics news on Phys.org


I thought for a second an asked, "Is it the probability that waves"? The lecturer thought for some moments and then aswered "yes".
No, to be precise. It's the quantum phase that waves (the thing that is responsible for the double-slit pattern). The probability is the squared amplitude of that wave, but it is possible for it to be constant, so the probability is not "waving", while the phase still does.

The only thing that comes to mind with "waving probability" is the superposition of particles with different masses, i.e. neutrinos or neutral kaon.

Or, in other words, my question is: what does the oscillating variable describe? For an em wave it is obvious, it is the magnitude of the electric or magnetic field. So, when describing the electron as a wave, is it still so?
It's nothing but the electron field. Not the electromagnetic field, but the electron field. Note that fermion fields are a bit different from boson fields.

...but, in that case: when an em wave behaves as a particle, a photon, can that photon also be described as a "probability wave", different from the em wave?
No, it can't, which is a flaw in QM, IMO.
 


What "waves" is really the mathematical construction of the quantum state. Take a particle in a box as an example; by solving the stationary S.E you get wave functions that are superpositions of two waves traveling in opposite directions. Of course, the physical interpretation of the solutions are found by taking the absolute square of the wave functions - the "waves" are left as mathematical building blocks.
 


In some experiments the electron behaves like a wave:

1) http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/davger2.html#c1"
You shoot electrons at a crystal and observe an interference pattern. The pattern can be explained if you assume that the electron has a wavelength.

2) http://www.perimeterinstitute.ca/Perimeter_Explorations/Quantum_Reality/Chapter_2_-_Wave-Particle_Duality_with_Electrons/"
(Chapter 2, Perimeter Institute for Theoretical Physics)
You observe dots on the screen but the pattern looks as if produced by wave interference.
 
Last edited by a moderator:

Similar threads

Undergrad "Wave-particle duality" and double-slit experiment
  • · Replies 36 ·
2
Replies
36
Views
9K
High School Can someone please explain to me the motion of an electron?
  • · Replies 11 ·
Replies
11
Views
3K
Undergrad Are electro-magnetic waves the same as the wave function?
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Non-wave solution to wave equation and virtual particles
  • · Replies 9 ·
Replies
9
Views
2K
High School Frequency of an EM wave in Classical and Quantum Physics
  • · Replies 6 ·
Replies
6
Views
2K
High School Question re photons/EM waves and the double slit experiment
  • · Replies 7 ·
Replies
7
Views
3K
Undergrad Are electromagnetic waves sine waves?
  • · Replies 3 ·
Replies
3
Views
3K
Undergrad Does the wave function spread more quickly after it is observed?
  • · Replies 32 ·
2
Replies
32
Views
4K
Undergrad Splitting of a one-particle wave function
  • · Replies 15 ·
Replies
15
Views
2K
Undergrad Interference of a fat laser beam: Tilting wave peaks
  • · Replies 8 ·
Replies
8
Views
2K