How does the electron make a photon in an antenna?

[raspberrypi]

We know how an electron makes a photon in an LED. It jump from a higher orbital to a lower one emitting a photon. But in an antenna its occupying the same valance just with a different nucleus each hop.  How is the energy transferred to a radio frequency photon?

[switchedmodepsu]

We know how an electron makes a photon in an LED. It jump from a higher orbital to a lower one emitting a photon. But in an antenna its occupying the same valance just with a different nucleus each hop.  How is the energy transferred to a radio frequency photon?

I like that you think deeper than the average person. LIKE!     

[phliar]

In the electron case, it's about energy: if an electron needs to get rid of some energy it makes the appropriate photon.

The antenna case is easier to think about classically -- you're making changing electric and magnetic fields when you send a signal down a conductor, and these changing electric+magnetic fields have this cool self-propagation ability that we call electromagnetic radiation. The QM analysis is left as an exercise for the reader... 

[calexanian]

I was taught, and I just did some google searching because its been so long, is that the actual radio wave propagation (In the common communication ranges) is purely electromagnetic and electrostatic based on Maxwells equations. They propagate independent of photons in a manner dictated by QED. The photons are just an emitted byproduct generated by the intrinsic energy of the signal itself. In other words an antenna is producing the EM field, but any photons that are being released are not the principal emission and nowhere near the frequency of the base band, or in other words the antenna does not emit electrons or photons as a primary mode, only fields. It emits no more photons than any other piece of metal with that amount of energy going on about it. Things get a bit more complicated as you go higher up in frequency though. Via QED more "Loss" of energy is expressed via photons until you have an infrared light source.  Somebody please correct me. Like I said. It has been a very long time.

[Rick Law]

We know how an electron makes a photon in an LED. It jump from a higher orbital to a lower one emitting a photon. But in an antenna its occupying the same valance just with a different nucleus each hop.  How is the energy transferred to a radio frequency photon?

You are thinking too classical.

Photon is a wave.  "radio frequency photon" is just another packet of energy.  EM wave doesn't need to convert itself into a packet of energy called "radio frequency photon" in order to travel.  You can think of EM wave travels by endless induction.  Moving E field induces M field which induces E field which induces...

Don't dig too deep into how EM wave or photon travels.  You can't describe it unless you get into quantum mechanics.  Once you get into quantum mechanics, you are not longer dealing with electronics.   Electronics is largely a macro-science rather than micro-(quantum)-science of traveling photons.

In reality, or rather, in quantum reality, I really don't know what it means even for a particle to travel from point A to point B.  We all just have models that we think describes the world, but no one knows for sure.

[MrOmnos]

We know how an electron makes a photon in an LED. It jump from a higher orbital to a lower one emitting a photon. But in an antenna its occupying the same valance just with a different nucleus each hop.  How is the energy transferred to a radio frequency photon?

Hey, I just took my Antenna and Propagation exam and something similar was asked. The classical explanation is the good old Maxwell's equations. Classical physics gives us a set of rules like Faraday's law and Ampere's law. As the name suggests these are just laws that we know nature obeys but as far as I have read, it doesn't really explain why part of thing? To explain why you need to get into quantum realm which is weird and spooky (literally). 

Here veritasium tries to exaplain EM with Special relativity.

[calexanian]

QED is not spooky. Its actually quite comforting to know that there is not simply magic, or turtles, or magic turtles governing the universe!

[djnz]

The classical explanation is fine, but does anyone have an insightful quantum flavored answer that is more than "because of the math"?

[T3sl4co1l]

Quantum doesn't matter, because there are no quantum corrections necessary.

In the classical domain, the [average] electron flow in the wires, the electromagnetic fields in the transmission lines and in space: all of this is given by waves, or fluctuations over the norm if you prefer.

In QM, precisely the same is true.  If you wish to break it down to the lowest possible level (photon-electron interaction), that's fine, but you won't learn anything about it.  It's not a discrete, free-space, ballistic interaction, but even the faintest signal involves the coherent (or incoherent and noisy!) interaction of billions of photons and sextillions of electrons.  While the underlying mechanism remains true, there is nothing to learn from it -- the only useful knowledge to gain comes from the statistical ensemble, where the large scale QM behavior trends asymptotically towards the classical model; very accurately indeed, as it happens.

Tim

[calexanian]

Perhaps this thought may help. Magnetic fields can exist completely independent of a particle carrier or medium. Particles can interact with the field, but they are not necessary for it to propagate.

[Rick Law]

Quantum doesn't matter, because there are no quantum corrections necessary.

In the classical domain, the [average] electron flow in the wires, the electromagnetic fields in the transmission lines and in space: all of this is given by waves, or fluctuations over the norm if you prefer.

In QM, precisely the same is true.  If you wish to break it down to the lowest possible level (photon-electron interaction), that's fine, but you won't learn anything about it.  It's not a discrete, free-space, ballistic interaction, but even the faintest signal involves the coherent (or incoherent and noisy!) interaction of billions of photons and sextillions of electrons.  While the underlying mechanism remains true, there is nothing to learn from it -- the only useful knowledge to gain comes from the statistical ensemble, where the large scale QM behavior trends asymptotically towards the classical model; very accurately indeed, as it happens.

Tim

Absolutely!  Electronics is a macro concept.  Quantum mechanics in general doesn't come into play.

The only place quantum mechanics will begin to matter is when we continue the miniaturization.  Traces in a die are now down to ~30nm.  At 10nm, you are talking about 100 atoms abreast.  Electronic at that level will begin to get iffy.

[T3sl4co1l]

Perhaps this thought may help. Magnetic fields can exist completely independent of a particle carrier or medium. Particles can interact with the field, but they are not necessary for it to propagate.

In the classical, E&M, "no luminiferous aether" sense, yes.

QED takes a very different view, however.

Tim

[T3sl4co1l]

Absolutely!  Electronics is a macro concept.  Quantum mechanics in general doesn't come into play.

Well... if "electronics" includes transistors, then...

But yes, if you're only doing design on a bulk level, then a transistor looks like a transistor with characteristic curves, and you don't need to look at the quantum behavior directly.

The only place quantum mechanics will begin to matter is when we continue the miniaturization.  Traces in a die are now down to ~30nm.  At 10nm, you are talking about 100 atoms abreast.  Electronic at that level will begin to get iffy.

You think RF is bad enough, where waves don't like to stay in wires?  At small enough scales, not even matter waves (at "DC") want to stay in wires!

Tim

[calexanian]

Absolutely!  Electronics is a macro concept.  Quantum mechanics in general doesn't come into play.

The only place quantum mechanics will begin to matter is when we continue the miniaturization.  Traces in a die are now down to ~30nm.  At 10nm, you are talking about 100 atoms abreast.  Electronic at that level will begin to get iffy.

It's not iffy if you believe in it enough. hahahaha. The electrons know how you feel about them!

[bson]

One of the classic Feynman lectures had a nice discussion of how magnetic fields and induction are required to preserve angular momentum... But I'll be damned if I can find the passage right now.  Anyone who hasn't seem these classic B&W lectures, absolutely should - the guy was a fantastic speaker.  Here's a collection of passages relating to the scientific method from the same talks... just brilliant. 

[raspberrypi]

We know how an electron makes a photon in an LED. It jump from a higher orbital to a lower one emitting a photon. But in an antenna its occupying the same valance just with a different nucleus each hop.  How is the energy transferred to a radio frequency photon?

I like that you think deeper than the average person. LIKE!     

Yea I try to think of EVERYTHING in terms of quantum physics. When I look at plastic I don't see an amorphous blob, I picture the hydrocarbon chain it makes. I ran a business and was good at seeing out of the box solutions that other couldn't. The phrase I hear alot around people is "Just ask Dave he will know." I don't think people have a personality, its just the manifestation of chemical reactions in your brain, ultimately decided down to quantum uncertainty. 

[CatalinaWOW]

There is no one way to look at it.  One thing that may make it a little easier to adjust to is by computing the RF photon energy, in eV or whatever unit works best for you.  You will find that each RF photon carries a tiny, tiny amount of energy.  Comparing that energy to the thermal energy variations in the valence electrons should give some insight into why the processes seem so different.

It is difficult to detect single optical photons, it is thousands to millions of times harder to detect single RF photons.  So you have to observe the bulk effects as described by Maxwell.

[rrinker]

One of the classic Feynman lectures had a nice discussion of how magnetic fields and induction are required to preserve angular momentum... But I'll be damned if I can find the passage right now.  Anyone who hasn't seem these classic B&W lectures, absolutely should - the guy was a fantastic speaker.  Here's a collection of passages relating to the scientific method from the same talks... just brilliant. 

 I didn't hit the one you were referring to yet, but thanks for sending me down THAT rabbit hole    Instead of going to bed I've been playing one after the other - there are 3 or 4 of the older ones like that that come up as related after each one, plus some of the more recent ones. Very easy to get sucked in and just keep hitting play on the next one.

[raspberrypi]

My understanding is this.
EMF is caused by real photons; they flow out of the radiator
Electric fields are caused by virtual photons, hence why things need to be touching (picometers distance) to interact
But magnetic fields are caused by what? In veritasiums video he explains how its special relativity due to perceived motion that causes a magnetic field becuause its just an electric field, but photons are real particles but are not emitted by magnets. If the gauge boson for magnetism is the photon where are the photons in a magnet? Virtual photons don't make sense on a macroscopic scale.

[HP-ILnerd]

A photon is an excitation in the electromagnetic field--just like any other particle is an excitation in its corresponding field.  It may not be a bad analogy to think of virtuals becoming real as similar to a signal going high in a Schmitt Trigger.  Any field can do it's thing without real particles being generated (E.g., the Higgs Field) because the Universe is a jittery place, but it takes energy to make a particle instantiate.  The vacuum, as an interacting set of fields, is sort of a blank canvas that has to be able to become anything that can be in it.

NB: The field notion (unsurprisingly) may seem reminiscent of the Luminiferous Aether concept.  The main (important!) difference is the fields in modern theory are all frameless:  you cannot measure your velocity relative to the fields as they all look the same regardless of your motion through them.

[Rick Law]

Photon and EM wave are the same thing.  To say EM wave make photons is rather like saying H₂O makes water.  Photon is a packet of EM wave energy.  EM wave traveling is a bunch of photons traveling.

U Colorado has a decent presentation on it - any physics department lecture would do as they all study the topic:
_{http://www.colorado.edu/physics/EducationIssues/ModernPhysics/Lecture_Notes/CSMSP11_Lecture11_AtomicSpectra(asgiven).pdf}

When energy is released in an atom, such as when an electron falls from a higher energy state to a lower energy state, it will emit a photon - that is the same as saying it will emit EM wave.  That released EM wave (photon) contains the energy it released.

Mass and energy are the same thing.  Photon (mass-less) carries momentum.

Photon and EM wave relationship is a different concept from wave-particle duality.  Wave-particle duality is the concept that all particles exhibits wave properties and the reverse is also true.  You can pick any subatomic particle, be it photon, electron, alpha particle, or for that matter, any particle.  When you treat it as a particle, you can measure it's particle properties.  When you treat it as a wave, you can measure its wave properties.  You will find alpha particles doing crazy things like being at two places at the same time when you are treating it as a wave.

Back to photon - current theory is, all EM waves travel at c.  However, there are studies pointing to possibly not all photons travel at c.  U.C. Davis study on how gamma ray appears to be slower is pointing at possibly not all photons travel at c.
_{https://www.ucdavis.edu/news/gamma-ray-delay-may-be-sign-new-physics/}

A lot of work are being done.  We don't know all there is to know yet.

[raspberrypi]

Perhaps this thought may help. Magnetic fields can exist completely independent of a particle carrier or medium. Particles can interact with the field, but they are not necessary for it to propagate.

Every force has to have a gauge boson. Strong=gluon Weak= W and Z bosons EM= photon, and gravity = graviton (not seen ...  yet). So the question here is what makes the photons for magnetic fields. Virtual photons are out because the ranges are too long, like 10^20th too long!

[T3sl4co1l]

Who are you to tell a photon how far to travel?

Tim

[raspberrypi]

Photon and EM wave are the same thing.  To say EM wave make photons is rather like saying H₂O makes water.  Photon is a packet of EM wave energy.  EM wave traveling is a bunch of photons traveling.

When energy is released in an atom, such as when an electron falls from a higher energy state to a lower energy state, it will emit a photon - that is the same as saying it will emit EM wave.  That released EM wave (photon) contains the energy it released.

Mass and energy are the same thing.  Photon (mass-less) carries momentum.

Photon and EM wave relationship is a different concept from wave-particle duality.  Wave-particle duality is the concept that all particles exhibits wave properties and the reverse is also true.  You can pick any subatomic particle, be it photon, electron, alpha particle, or for that matter, any particle.  When you treat it as a particle, you can measure it's particle properties.  When you treat it as a wave, you can measure its wave properties.  You will find alpha particles doing crazy things like being at two places at the same time when you are treating it as a wave.
work are being done.  We don't know all there is to know yet.

OK but there must be different mechanism to radiate sub Infrared (longer) photons. When a wire generates a radiowaves no electrons are jumping from a higher orbital to a lower one as is the case to make IR light UV and Xrays (balmer series etc). The longer the jump the higer energy/shorter wave length photon. IR seems to emitted by phonons in matter as way to get rid of thermal energy. But what happens at lower energies?   

[Vtile]

You can create radiotion also by changing the direction of electron rapidly or by driving it faster than the speed of light (sorry for a wrong term here, but I can not get the right "relatively light speed" term to my head) in dielectric. Goes over my understanding/knowledge what you want to call it, but yep.

https://en.wikipedia.org/wiki/Synchrotron_radiation
https://en.wikipedia.org/wiki/Bremsstrahlung
https://en.wikipedia.org/wiki/Cherenkov_radiation (I like that it were predicted by heaviside, would have been interesting to go to get a beer with him.)

Those Feyman lectures, whoa. Spend 3 hours already.