Electromagnetic radiation is the acceleration or deceleration

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Discussion Overview

The discussion revolves around the nature of electromagnetic radiation, specifically whether it is produced by the acceleration or deceleration of charged particles, particularly electrons, and the relationship between bound and free electrons in this context. Participants explore concepts related to energy levels, virtual photons, and the conservation laws governing these processes.

Discussion Character

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

Main Points Raised

  • Some participants propose that electromagnetic radiation originates from the acceleration or deceleration of charged particles, primarily electrons, while also noting that photons are emitted when electrons transition between energy levels.
  • Others argue that there is no contradiction between these scenarios, as bound electrons and free electrons behave differently in terms of energy levels and radiation emission.
  • One participant mentions that the energy spectrum for free electrons is continuous, whereas for bound electrons, it is discrete.
  • A question is raised regarding whether photons emitted and absorbed by free electrons are considered virtual photons, leading to a discussion about the nature of virtual particles and their role in force exchanges.
  • Another participant expresses confusion about virtual particles, suggesting that free electrons may not emit real photons due to energy constraints, but may emit and absorb virtual photons according to the time-energy uncertainty principle.
  • One participant describes two phenomena: the behavior of an electron at rest, in uniform motion, and when accelerating, and how these relate to the formation of electromagnetic waves.
  • Another point made is that conservation laws, such as energy and momentum, prevent free electrons from emitting free photons, and that virtual particles may briefly exist due to energy uncertainty but must be reabsorbed to maintain conservation laws.

Areas of Agreement / Disagreement

Participants express a range of views on the relationship between free and bound electrons, the nature of virtual photons, and the implications of conservation laws. The discussion remains unresolved, with multiple competing perspectives presented.

Contextual Notes

There are limitations in the understanding of virtual particles and their implications for free electrons, as well as the complexities surrounding energy conservation in the context of photon emission.

Ratzinger
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the source of all electromagnetic radiation is the acceleration or deceleration of charged particles, mostly electrons….only when an electron jumps down energy levels, a photon/ electromagnetic wave is emitted…sounds contradicting to me, how can be both correct?

Hope question isn’t too silly.
 
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When electrons are jumping up and down energy levels they're bound to atoms. In the other scenario you have free particles. There's no contradiction.
 
The energy spectrum for the free electron is continuous,while for the bounded one is discrete.

Daniel.
 
Thank you, that makes sense.

Are the photons emitted and absorbed by free electrons then virtual photons?
 
What do you mean by "then virtual photons"?It's all about reading correctly a Feynman diagram.

Daniel.
 
Well, there is where the problem starts, I have no clear idea of what virtual particles are, only heard that all forces work by exchanging bosons which are virtual and that these virtual carrier particles only exist during this exchange process.

I remember also reading somewhere that free electrons don't have the energy (as opposed to bound electrons) to emit real photons, but according to time/energy uncertainty every free (and accelerating?) electron emits and absorbs virtual photons.

But I believe I confused a lot. Could you help me out?
 
First Phenomena

Electron at rest has an electric field, when in uniform motion, has constant magnetic field at a point,when accelerating has a changing magnetic field, and as a changing magnetic field induces a changing electric field,therefore an accelerating electron forms an electromagnetic wave.


Second Phenomena

When an electron jumps from one energy level to another , the difference in energy levels is emitted as a radiation of same electromagnetic wave of the same energy.
 
well, you need to conserve Energy-impulse, that is why one free electron cannot emit one free photon. Then orbital momentum, electron charge, and some other stuff should be consserved as well, that is why electron cannot emit two photons (not sure about that, but an inquiring person could find this out relatively straigforwardly).
As to virtual particles, they say that an energy uncertanity allows to emit a photon for a short time, but it should be reabsorbed for the conservation laws to hold.
 
Much thanks so far. Could someone talk about free electrons and virtual photons a little bit more.
 

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