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I am trying to sort out my understanding regarding Photons. I understand the Electromagnetic Spectrum contains all radiation (energy) in all wavelengths (light) consisting of Photons. This can be broken down into Photons involving Waves and Packets- Electric and magnetic fields. The more Packets of Photons = the faster the wavelength which is the same as higher frequency/closer wave peaks.

My best at understanding Electrons involves Electrons not creating energy themselves, but rather, simply act as a way to transport energy and have different levels of energy. I can also go as far as to say that when a level of energy is shifted closer or away from the Electron, the result is a shift in Light emitted as a reaction from the shift- and therefore; Photons are at work to represent the change in light within the Spectrum. I am looking at the EM Spectrum and focusing on the part I work with, Radio Waves, I can go into the endless theory which modern technology is based off of to create electronics, circuitry, and wireless propagation of radio waves transmitted and received from antennas.

THIS IS MY QUESTIONS: If the EM Spectrum makes up all frequencies what is the connection between Photons and Electrons in electronics, mainly in RF Propagation? I am still new to quantum mechanics and my goal is to understand Photons. My cup is empty and any help would be greatly received. I admit I am still learning and I apologize ahead of time for trying to get a grasp on my lack of understanding. If Photos have no mass, yet make up the EM Spectrum through wavelength and packets and if Electrons have atomic mass and make up Radio Theory as we know it today then how is any of this even possible? How does the Electron have a relationship with the Photons to make RF Propagation work? The only theory I can ponder are Photons are the waves which Electrons ride on to pass/conduct energy which circuits use...? I won’t even ask what is Energy (at its start in the raw birth), rather just simply accept something provides a form of power/current/charged atoms which are manipulated to interact with electrical devices.

Or, am I simply at trying to understand an ongoing division between normal physics with Hertz and Electrons vs Photons and QM?

Any help would be amazing.

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Thank you both for your explanation! I was trying to understand a direct connection between the two different areas of Small and Large scale Physics- QM with Photons vs classical behavior of Electrons in Maxwell. I now have a clear area to run in and dive more efficiently into learning both foundations more. I can see how I truly need to understand both, separately, before I can make the connection between the two in any grand scale of understanding. –  crutch Apr 6 '12 at 15:54

2 Answers 2

One should first understand the two separate successful systems of describing electromagnetic radiation and the place of the electron in each before trying to see how and at what limits one blends into the other.

The first system is Maxwell's equations and the classical behavior of electrons with electromagnetism. Maxwell's equations allow for waves of electromagnetic radiation of frequency nu, and the conductivity of metals dependents on electron motion; it foresees the radiation of electromagnetic waves from accelerated electrons, whether in magnetic fields or any other fields.These electromagnetic waves cover the whole spectrum of frequencies/wavelengths as emitted by an antenna, for example. The classical explanation is the acceleration of the electrons in the antenna as the fields applied are changed.

This is a robust system of describing electricity magnetism and electromagnetic radiation, except for some exceptions that can only be described by the second system which emerged when the microscopic behavior was found to differ from the classical expected behavior.

The second system is the quantum mechanical description of matter which usually deals with very small numbers and dimensions but sometimes the aggregate behavior of matter shows quantum mechanical traits, as with transistors, for example. It is also necessary macroscopically to describe superconductivity and superfluidity . In this QM system, electrons are bound to atoms in potential wells which allow only specific energy levels. If an electron falls into the potential well, it gives up electromagnetic energy in fixed quanta, which are the photons. These have been found experimentally to behave as particles in the way they are absorbed and the way they transfer energy. In metals the potential well of the atoms can give an aggregate potential well which allow the electrons to exist as a sea of electrons, the fermi level. These photons have energy=h*nu, where h is the Planck constant.

In a similar way that thermodynamics and statistical mechanics blend into each other at the limit of large numbers of particles, classical electromagnetic theory and quantum mechanics with photons blend when the number of photons is very large. This means that the RF frequency created by the acceleration of electrons in the antenna, in the quantum mechanical frame consists of an enormous number of individual photons each with energy=h*nu characteristic RF frequency, created by transitions of electrons in the fermi level potential description.

So you have to concentrate in understanding the two systems separately, before trying to visualize the limits at which they run into into each other.

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Photons and Electrons belong to two different categories of particles i.e Bosons and Fermions respectively.

Classically we can say that an accelerated charge produces EM wave or Quantum mechanically we can say that an electron transitioning from one state to another state (with lower energy) emits a photon. In radio antenna we have oscillating (and thus accelerating) electrons which produce radio waves.

Also electrons do not ride on photons, they are moving in electrical circuit while photons travel in air or free space. I have included some links here, maybe these can help:

http://www.cdt21.com/resources/guide2.asp

http://physics.ucsd.edu/~tmurphy/phys8/lectures/13_radio.pdf

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