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When we view a photon as a wave, do the sides of the wave possess less energy than the center of the wave.
Look at this photo:

Photo

that should help make sense of what I mean.

a reply to: IAmTheRumble

Apparently it's not squiggles but it's a fluctuation between the e and the H field.
The amount of times they fluctuate/ oscillate in a given measurements gives their frequency.

a reply to: IAmTheRumble
Yep. The photon arrives as a fade-in, achieves a maximum, and tapers off in a fade-out.

originally posted by: IAmTheRumble
When we view a photon as a wave, do the sides of the wave possess less energy than the center of the wave.

Note your source calls the drawing "whimsical". I'm not sure how to make a non-whimsical drawing that would accurately reflect all the properties of photons as we understand them through experiments. The answer I think is "no", that's not the correct interpretation of that drawing.

originally posted by: Pirvonen
a reply to: IAmTheRumble
Yep. The photon arrives as a fade-in, achieves a maximum, and tapers off in a fade-out.

That's not how I interpret it. I think I posted this earlier in the thread, which shows how I interpret the wave packet, as a measure of probability of finding the entire photon, not how the photon fades in and out:

a reply to: Arbitrageur

Except the damn drawing's got that squiggle in it to iconically let you know they're talking about a wave...however, the photon does not bounce up and down, nor do the em components. It's very confusing to some people.

a reply to: Bedlam

How do you feel about the old analogy in regards to Electric and Magnetic fields and the the rope that's going up and down while simultaneously left and right? Basically correct or also misleading.

While were at it anybody want to take a stab at explaining the Curled A field, or is Vector Potential no fun to explain?

originally posted by: Bedlam
It's very confusing to some people.

Yes, the confusing part here is there's more than one type of wave involved. The photon has EM waves related to its frequency, but the "whimsical drawing" IAmTheRumble referred to doesn't refer to that, but instead refers to a probability plot resulting from the "wave function" which is something else. For example, you can also make wave function probability plots of electrons like in IAmTheRumble's drawing, but electrons don't have an electromagnetic frequency, like the photons do, so I can understand why it's confusing.

originally posted by: ImaFungi

originally posted by: mbkennel


It means that the quantum mechanical threshold for particle creation in electromagnetic fields is higher for high frequencies than for low frequencies.

You are attempting to evade the question.

Define a single photon.

The state of the wavefunction of the expansion of the electromagnetic field after you apply the creation operator to it.

And then state how that definition of a single photon, can contain the concept of frequency?

Because you can expand the wavefunction of the electromagnetic field in a momentum basis and that also gives the frequency.

Is a single photon a full crest and a full trough? Or half and half? And then what is the nature of the ends, are they frayed? Are they pointy? How thick are they?

Actually depends on what basis you use to expand the electromagnetic field & its wavefunction. It's somewhat dependent on the boundary conditions you impose. It's similar to expanding EM field classically in a waveguide.

Of course I am not thinking about it right when I say those things, because the photon is not a object like thing, like a rope, which can have troughs crests and edges.

But a photon is the result of things, electric field and magnetic field. As sound is the result of things, air molecule and air molecule. Photon is 'the in between'.

more complex than that. QM of a particle: a wavefunction of a point x,y,z. QM of a field, a wavefunction/functional of a vector valued field [E(x,y,z,t),B(x,y,z,t]). Now think about basis expansions in both wavefunction and field.

Yes, it gets complex and abstract. Suck it up.


www.eng.fsu.edu...

This is a good start on the problem"

physics.stackexchange.com...

This is a reasonable question to ask, but the answer is probably not what you're expecting: the electric and magnetic fields don't have well-defined values in a state with a fixed number of photons. The electric and magnetic field operators do not commute with the number operator which counts photons. (They can't, because they are components of the exterior derivative of the field potential operator, which creates/annihilates photons.) The lack of commutativity implies via Heisenberg's uncertainty principle that the field might have arbitrarily large values.

If you have a single photon in most bases, then that implies that there is a wavefunction which, if you were to take expectation of electric and magnetic fields, means that there is a probability density for finding the E and B fields in various configurations.

It's a functional, as E and B are themselves functions of space, and then the wavefunction could be a function which takes a function as its argument. What does that "look like"? No clue. I couldn't possibly cognitively visualize a function of functions of 3+1 space, much less its basis functinos.

This is quantum optics. In the end, in principle, questions which relate to observables can be answered, but not ones which relate to internal human cognitive assumptions.

removed

Since it has been discovered That high energy photon collisions can create The basic building blocks of matter, Then why are photons not considered the Fundamental building block of reality?

a reply to: dashen
I suppose in one sense that interpretation might be at least partly correct in light of this theory about the origin of the universe:

originally posted by: ErosA433
As said, the early universe is thought to have been entirely energy dominated, from the theroetical beginning, through the inflation era, during this phase, the dynamics of the universe where entirely set by high energy photons and neutrinos probably. A complex soup of photons, likely dark matter and then neutrinos, in all it would be mostly energy and very little stable matter, what ever matter is produced would quickly decay back to photons, or be transmuted in some way by photons and then back into energy.

However, instead of photons, one might think what's fundamental is energy, since that's how we think the universe started out, which later partly "condensed" into what we see today, though the universe is still mostly energy in a form we don't fully understand (dark energy), and dark energy doesn't seem to have anything to do with photons.

So can we really say photons are the fundamental building blocks of reality if most of reality appears to be "dark energy", whatever that is? It seems to not be photons, or if it's built from photons, I have no idea how. We think it might be vacuum energy but I think that's one of the least understood things in physics.

a reply to: dashen

I've often wondered that myself. I'm actually reading about something similar.

Question fro the physics gurus.

Pions. The proton has two up and one down quark. The neutron the up and two down quarks. Wouldn't this mean for symmetry sake there is a very weak cloud of virtual Pions Up Down, Up up, Down down pions surrounding the proton or neutron?

a reply to: Arbitrageur

Yeah that is one of those things, I would really need to check my UG notes but I thought that inflation was basically an era so to speak when spacetime itself is kind of condensing, so, hmmmm how do we think of this?... maybe something like space condensing out of energy? A point in the universe where the coupling between energy itself and space time becomes decoupled? so the CMB era would really kind of be defined mainly in terms of a high energy soup of photons, probably some leptons higher energy quarks and gluons all mixed up... the universe is still 'hot at that time.

didnt really include say Dark Matter or supersymmetry implications, but we would assume this is produced in abundance at some point in the process, likely during the same cooldown period

Might have that completely wrong, its been a very very long time since i did cosmology haha need to really get some books out

a reply to: Arbitrageur

But when you say energy what type of energy? Potential energy? Kinetic energy? Pressure differentials?

a reply to: dashen

Those are really only two forms of energy, not 3, since a pressure differential is a kind of potential energy... the answer would be... both...

a reply to: ErosA433

So everything in the universe at its basis is really potential or kinetic energy?

originally posted by: dashen
a reply to: ErosA433

So everything in the universe at its basis is really potential or kinetic energy?

I think about 99% of your mass can be attributed to energy, mostly energy of the gluon fields in your atomic nuclei and the kinetic energy of the quarks inside. The other about 1% of your mass is from the mass of the quarks and electrons and I'm not really sure if those are a form of energy but you at could say they "condensed" out of the big bang energy according to theory.

But the stuff you and I and the Earth are made of accounts for only 5% of the known universe. We don't understand the other 95% (Dark matter and dark energy), so I'd be reluctant to make statements about "everything in the universe" with such a huge gap in knowledge as 95%, maybe 96% depending on whose figures you look at. Dark matter is the biggest unknown and Eros and his associates are trying to figure that one out.

a reply to: Arbitrageur

Is dark matter tangible?
What would it taste like?

a reply to: dashen
Warm apple pie.

originally posted by: dashen
a reply to: Arbitrageur

Is dark matter tangible?
What would it taste like?

In the last second probably over a trillion neutrinos passed right through your body and you didn't even notice. One guess about dark matter is that it could do the same thing but it's even harder to detect than neutrinos, which is why Eros is building better detectors, but he knows way more about them than I do.

I suggest reading his thread on direct dark matter detection to learn more about that.