Anonymous at Sun, 13 Oct 2024 08:43:47 UTC No. 16424500

Assuming electrons in atoms, that can respond to a field like a harmonic oscillator, is a good start.
You then get the typical differential equasions for a dampned harmonic oscillator.
You get a refractive index with real and imaginary part. For metals the imaginary part is most important, because this will result in a dampened oszillation and absorption.
The refractive index then relates via the fresnel equasions to what you mentioned.
And even mirrors cant be used everywhere, since most mirror coatings are metalic. Electron gases in metals stop responding after the plasma frequency. i.e. x-rays just pass through a mirror.

Anonymous at Sun, 13 Oct 2024 09:16:30 UTC No. 16424534

>>16424500
>light slowing down in material
Nothing controversial about that.
>light slowing/speeding up due to gravity
Noooo!!! It must be time that is slowing/speeding up!

Anonymous at Sun, 13 Oct 2024 09:20:53 UTC No. 16424540

>slowing down

No... NO STOP
It's not SLOWING DOWN. It's just not going in a straight fucking path. It's bouncing around, getting absorbed and transmitted and reflected.
Between collisions it is still going at the speed of light in vacuum

Anonymous at Sun, 13 Oct 2024 09:26:43 UTC No. 16424552

>>16424540
there would be a few photons that shot through at full speed if that were the case.

Anonymous at Sun, 13 Oct 2024 10:52:28 UTC No. 16424870

>>16424552
why? why is that absolutely necessary?

Anonymous at Sun, 13 Oct 2024 10:54:20 UTC No. 16424879

>>16424552
wrong
https://physics.stackexchange.com/questions/524747/do-photons-actually-slow-down-in-a-medium-or-is-the-speed-decrease-just-apparen

Anonymous at Sun, 13 Oct 2024 11:06:31 UTC No. 16424941

>>16424540
This is actually not correct, the light is not absorbed in this way. If it did how will the atom remember in which direction to emit it? So in this case light will just scatter instead of going in straight line.

Anonymous at Sun, 13 Oct 2024 11:17:39 UTC No. 16425022

>>16424941
https://en.m.wikipedia.org/wiki/Ewald%E2%80%93Oseen_extinction_theorem

Anonymous at Sun, 13 Oct 2024 11:24:49 UTC No. 16425084

>>16424534
>light slowing/speeding up
>time slowing/speeding up
Literally the same thing

Anonymous at Sun, 13 Oct 2024 11:32:17 UTC No. 16425145

>>16424324
1/2
tl;dr refraction depends on the chemical bonds of the material, not molecular weight.

Maxwell's equations in matter are picrel. Here, [math]\mathbf{D} = \mathbf{E} + \mathbf{P}[/math], where [math]\mathbf{P}[/math] is the (macroscopic) polarization vector of the given material. A similar equation holds for [math]\mathbf{H}[/math], but materials used in optics are insulators, so they have negligible magnetiziation and one assumes [math]\mathbf{H} = \mathbf{B}[/math]. For the same reason, there are no free currents in optical materials, so [math]\mathbf{J}=0[/math]. We also assume that optical materials have no static charge, so [math]\rho = 0[/math]. This leaves us with
[eqn]\nabla \cdot (\mathbf{E} + \mathbf{P}) = 0[/eqn]
[eqn] \nabla\cdot\mathbf{B} = 0[/eqn]
[eqn]\nabla\times\mathbf{E} = -\frac{1}{c}\frac{\partial\mathbf{B}}{\partial t}[/eqn]
[eqn]\nabla\times \mathbf{B} = \frac{1}{c}\frac{\partial}{\partial t} (\mathbf{E} + \mathbf{P})[/eqn]
When you take the curl of the last two equations and use the first two to make simplifications, you end up with
[eqn]\nabla^2\mathbf{E} - \frac{1}{c^2}\frac{\partial^2\mathbf{E}}{\partial t^2} = \frac{1}{c^2}\frac{\partial^2\mathbf{P}}{\partial t^2} - \nabla(\nabla\cdot\mathbf{P})[/eqn]
[eqn]\nabla^2\mathbf{B} - \frac{1}{c^2}\frac{\partial^2\mathbf{B}}{\partial t^2} = -\frac{1}{c}\nabla\times\frac{\partial\mathbf{P}}{\partial t}[/eqn]
which are two inhomogeneous wave equations. The speed of light in these equations is still [math]c[/math], even though its propagating in a medium.

Anonymous at Sun, 13 Oct 2024 11:45:43 UTC No. 16425267

>>16425145
2/2
Now, to solve these equations, one assumes some functional form of [math]\mathbf{P}(\mathbf{E})[/math]. Most materials have a linear, isotropic response, ie
[eqn]\mathbf{P} = \chi \mathbf{E}[/eqn]
where [math]\chi[/math] is a material-dependent parameter called (electric) susceptibility. With this assumption, the two equations above reduce to
[eqn]\nabla^2\mathbf{E} - \frac{n^2}{c^2}\frac{\partial^2\mathbf{E}}{\partial t^2} = 0[/eqn]
[eqn]\nabla^2\mathbf{B} - \frac{n^2}{c^2}\frac{\partial^2\mathbf{B}}{\partial t^2} = 0 [/eqn]
where [math]n = 1/(1+\chi)[/math] is the refraction index. This is now a HOMOGENOUS equation with APPARENT velocity [math]v = c/n[/math].

However, not all materials are isotropic and linear. The general functional form is polarization may be some complicated function of the electric field. One usually performs a Taylor expansion
[eqn]P_a = \chi^(1)_{ab}E_b + \chi^(2)_{abc}E_bE_c + \ldots[/eqn]
where susceptibility is now a tensor due to anisotropy (eg due to long polymer chains). You can quickly check that one can no longer define the refractive index as just some constant that "slows down" light. This apparent phenomenon is only there due to assumption of linearity and isotropy. In the general case, we end up with a very complicated non-linear differential equation (see part 1) that doesn't admit an easy interpretation as a "slowed down" way.

Anonymous at Sun, 13 Oct 2024 12:00:02 UTC No. 16425442

>>16425267
This is just a bunch of theorycel jibberish that ultimately doesn't tell you anything more than what you already knew, v=c/n. >>16424534
Yeah, refraction was my first clue that special relativity couldn't be correct.

Anonymous at Sun, 13 Oct 2024 12:02:43 UTC No. 16425481

>>16425442
The whole point of my post is that v = c/n only holds for linear, idotropic media. Non-linear or anisotropic media don’t admit such an interpretation.
>muh gibberish
brainlets can’t handle undergraduate math lmao

Anonymous at Sun, 13 Oct 2024 12:36:48 UTC No. 16426116

How does the light speed up after leaving the glass?

Anonymous at Sun, 13 Oct 2024 12:37:08 UTC No. 16426128

>>16425442
As for your comment on "special relativity" (you're talking about general relativity), one does the exact same thing I described above by defining the displacement tensor [math]D_{\mu\nu} = \sqrt{-g} g_{\mu\alpha}F^{\alpha\beta}g_{\beta\nu}[/math]. One can then talk about polarization and refraction due to gravity. But since the metric [math] g_{\mu\nu}[/math] is usually a non-linear function of coordinates, the same v = c/n interpretation only holds in the lowest order approximation (ie weak gravitational fields "slow down" light). In the general case, this simple interpretation no longer holds. So Einstein isn't wrong in the slightest. You're just a brainlet who takes approximations as true solutions, because that's all you were ever exposed to.

Anonymous at Sun, 13 Oct 2024 12:44:58 UTC No. 16426308

>>16424324
>light goes through different materials at different speeds
That's wrong already. Didn't read the rest.

Anonymous at Sun, 13 Oct 2024 12:45:48 UTC No. 16426328

I've come to the conclusion that those pushing for classical physics are communists inspired by the objective materialist philosophy of Marx.

Anonymous at Sun, 13 Oct 2024 12:48:38 UTC No. 16426379

>>16424941
>how will the atom remember in which direction to emit it?
Conservation of momentum.
>>16424879
I've never read such a bad stackexhange post. It's not even halfway correct what they wrote there.

Anonymous at Sun, 13 Oct 2024 12:53:43 UTC No. 16426479

>>16426328
>physics stagnating exactly the moment jewish schizophrenic rambling became unquestionable dogma
It must be a coincidence goy!

Anonymous at Sun, 13 Oct 2024 13:54:17 UTC No. 16427636

>>16426379
>Conservation of momentum.
Momentum is conserved during the absorption, and then conserved again at a later time during the emission, if you also consider the motion of the atom. There is no law of nature that says these two directions have to be the same.

MORON NUGGER

Anonymous at Sun, 13 Oct 2024 13:55:51 UTC No. 16427653

>>16427636
>There is no law of nature that says these two directions have to be the same.
Conservation of momentum.
hint: momentum is a vector

Anonymous at Sun, 13 Oct 2024 14:05:49 UTC No. 16427744

>>16427636
This is the typical nu-/sci/ poster lmao
>Momentum is conserved during the absorption, and then conserved again at a later time during the emission
And in-between, momentum does whatever it wants, eh?

Anonymous at Sun, 13 Oct 2024 14:52:04 UTC No. 16428056

>>16424324
ITT anon discovers plasmonic metamaterial super lenses.

Anonymous at Sun, 13 Oct 2024 14:55:03 UTC No. 16428080

>>16426479
Einstein was dogmatically against the QM, something tells me you don't like QM either

Anonymous at Sun, 13 Oct 2024 15:20:47 UTC No. 16428243

>>16424534
Look up what phase velocity is

Anonymous at Sun, 13 Oct 2024 15:57:56 UTC No. 16428432

>>16427744
>>16427653
this is what we take advantage of when we laser cool neutral atoms. You niggermoron

Anonymous at Sun, 13 Oct 2024 16:53:40 UTC No. 16428696

>>16428432
>a change in momentum of one thing breaks conservation of momentum
Experimental physicists were a mistake.

Anonymous at Sun, 13 Oct 2024 16:58:16 UTC No. 16428724

>>16428696
*stops walking*
NOO YOUR MOMENTUM CHANGED ITS NOT CONSERVED OMG WHAT IVHACE DONE *ACK*

Anonymous at Sun, 13 Oct 2024 17:03:56 UTC No. 16428745

>>16428724
You applied a force with your muscles.

Anonymous at Sun, 13 Oct 2024 17:53:00 UTC No. 16428925

>>16428724
>Yo asteroid wassup, why are you floating through space with constant velocity though?
>You can literally just stop, bro

Anonymous at Sun, 13 Oct 2024 18:47:30 UTC No. 16429088

>>16428724
Riddle ne this, lab monkey:
What does the little funny arrow on [math]\mathbf{k}[/math] mean in the formula
[math]\vec{\mathbf{p}} = \hbar \vec{\mathbf{k}}[/math]
?

Anonymous at Sun, 13 Oct 2024 18:51:06 UTC No. 16429099

>>16424534
>>16424540
OP here, i don't know how it works exactly but i'm aware that light being slowed down is just a macroscopic, "black "box" outside perspective. I didn't adress that because it's not what my post is about primarily, but the question what actually "slows down" the progression of light through the medium as a whole of course touches upon that.

>>16424500
>>16425145
>>16425267
off the bat and without really diving into it, i'm taking that it doesn't just depend on the number of electrons in the medium
>tl;dr refraction depends on the chemical bonds of the material, not molecular weight.
That can't be all of it because even noble gases with no bonds at all have refractivities, xenon even has a higher refractive index than hydrogen.
Also, alkaline metal halides with almost 100% ionic bonds have pretty decent refractive indexes.

Anonymous at Sun, 13 Oct 2024 20:22:56 UTC No. 16429327

>>16424324
You're asking dangerous questions. Don't prod further if you know what's good for you.

Anonymous at Sun, 13 Oct 2024 20:51:15 UTC No. 16429389

>>16428745
>>16428925
>>16429088
>ITS DIFFERENT WHEN A MOLECULE ABOSRBS A PHOTON OK?? IT JUST IS!
lmao..

Anonymous at Sun, 13 Oct 2024 20:56:56 UTC No. 16429406

I'm a layman, but when I looked into refraction at the microscopic level I thought the reason for light moving slower was because the light is absorbed and re-emitted by all the particles in the medium and the ones perpendicular to the angle of incidence interfere with each other canceling them out, same goes for the ones travelling backwards (incoming overwhelms backwards ones so they can be ignored) leaving only the ones travelling in the same direction unobstructed. The absorption and emission is not instant which makes it looks like light is travelling slower.

The bend was something like the light getting pulled towards the particles instead of flying straight into them because they are now approaching an interface at an angle (with different particles haven't different field strengths pulling and thus different angles) which basically biases the photons to that side and makes the absorb - emit bias lean in that direction. the reverse then happens when it exits the medium

could also be completely wrong on all that

Anonymous at Sun, 13 Oct 2024 21:02:26 UTC No. 16429423

>>16429406
>i'm a layman
>*me skipping to last paragraph*
>could also be completely wrong on all that
thank you for playing

Anonymous at Sun, 13 Oct 2024 21:02:27 UTC No. 16429424

>>16429099
NTA, and not yet taken any advanced optics, but I’ll try to answer the chemical bonds statement: from what I can gather it’s because noble gases still have intermolecular forces (van der Waals forces) and thus still have correlations in polarities of each atom that then refracts light. As for xenon, it has a high atomic number and fully filled shells, and is fairly down the group 18 elements so its combined size when interacting with another xenon atom is higher than the size of molecular hydrogen. This means its polarizability and van der Waals forces are higher than hydrogen, increasing its refractive index relatively despite hydrogen’s chemical bonds. The refractive index is also proportional to molar density, and xenon has a higher molar density at STP than molecular hydrogen, which further helps it have a greater index.

Anonymous at Sun, 13 Oct 2024 21:06:19 UTC No. 16429438

>>16429406
There is no absorption / re-emission occurring. It's an interaction effect between the incoming electromagnetic waves and the electromagnetic fields produced by the atoms in the material. Think of it like the interference between two waves producing a new waveform with a reduce phase velocity.

Anonymous at Sun, 13 Oct 2024 21:09:40 UTC No. 16429449

>>16429438
I thought I remember reading that the absorb / reemission was in fact happening, it wasn't some wave shenanigans?

Anonymous at Sun, 13 Oct 2024 21:10:52 UTC No. 16429454

>>16429099
You can see from the equations I provided that we’re talking about chemical bonds under the condition of applied electric fields. Even in noble gases, an applied electric field will pull the electrons on the orbitals in the direction of the field, thus creating microscopic polarization. It’s really all down to stuff being made of charged particles that respond to external electric fields. Complex chemical bonds just make this response much more complicated in nature.

Anonymous at Sun, 13 Oct 2024 21:11:04 UTC No. 16429455

>>16429438
There is no wave happening. The photon is not a wave.

Anonymous at Sun, 13 Oct 2024 21:11:12 UTC No. 16429456

>>16429449
They were wrong. It's a commonly told misconception.

Anonymous at Sun, 13 Oct 2024 21:13:20 UTC No. 16429460

>>16429455
Quantum mechanics would say otherwise.

Anonymous at Sun, 13 Oct 2024 21:25:10 UTC No. 16429487

>>16429460
You don’t have to go that far. Hamilton-Jacobi mechanics (which is classical) would say the same.

Anonymous at Sun, 13 Oct 2024 21:31:06 UTC No. 16429503

>>16429487
a model being able to explain a phenomena is irrelevant, this thread is more about what is *actually* happening as far as we understand

Anonymous at Sun, 13 Oct 2024 21:32:24 UTC No. 16429506

>>16429389
Anon, we're not saying it's different. You are. You don't understand simple conservation of momentum.

Anonymous at Sun, 13 Oct 2024 21:35:57 UTC No. 16429513

>>16429503
Then there is no point in doing physics as it’s all models. Even Newton’s laws are models of how macroscopic objects move and break down under certain limits (relativity and QM)

Anonymous at Sun, 13 Oct 2024 21:37:06 UTC No. 16429516

>>16429506
I literally said momentum was conserved and you said it wasnt. You seemingly have different rules for absorption.

Anonymous at Sun, 13 Oct 2024 21:40:24 UTC No. 16429522

>>16429506
Like any quantum object, thinking of it either as a classical wave or a classical particle can only be an analogy or approximation. When they are propagating, a wave description works best, and when they are absorbed or emitted, a particle

Anonymous at Sun, 13 Oct 2024 21:58:17 UTC No. 16429554

>>16429516
No. You said >>16427636
>direction of momentum is irrelevant
which is very different from how other systems work. Recall that this is in response to your question of how the system remembers the direction of an incoming photon.

Anonymous at Sun, 13 Oct 2024 21:59:18 UTC No. 16429557

>>16429516
Also
>Conservation of momentum
is literally the first thing I posted ITT.
>>16429522
I know. And?

Anonymous at Sun, 13 Oct 2024 22:08:44 UTC No. 16429585

>>16429557
so the photon is not a wave. QM does not say what you said

Anonymous at Sun, 13 Oct 2024 22:15:37 UTC No. 16429608

>>16429503
What is actually happening is you see a light ray bend. Anything beyond that is going to be a model. Whether it’s actual math or linguistic “arguments” doesn’t make an ounce of a difference.

Anonymous at Sun, 13 Oct 2024 22:21:26 UTC No. 16429619

>>16429608
and bending does nor require speed to change merely direction

Anonymous at Mon, 14 Oct 2024 04:19:37 UTC No. 16430230

>>16429585
I never said anything about waves. Are you dumb or did you reply to the wrong post?

Anonymous at Mon, 14 Oct 2024 06:37:20 UTC No. 16430386

>>16429619
Yes. Trouble is, velocity is what’s important here, not just its magnitude (speed). /sci/ should have an obligatory captcha with basic linear algebra to filter retards like you.

Anonymous at Mon, 14 Oct 2024 06:39:25 UTC No. 16430391

>>16430386
>You're right
>Therefore, you shouldn't be able to post here
What is it with mongoloids like you that makes them so insufferable?

Anonymous at Mon, 14 Oct 2024 06:43:45 UTC No. 16430398

>>16430391
I never said you’re right. Look up what a vector is. Only mongoloids know, apparently.

Anonymous at Mon, 14 Oct 2024 06:56:22 UTC No. 16430410

>>16430398
>>Speed does not necessarily change, direction has to
>Yeah you're right but you're wrong because it's not the magnitude it's the direction that's important
You are beyond help.

Anonymous at Mon, 14 Oct 2024 08:06:27 UTC No. 16430472

>>16430410
>Give not that which is holy unto the dogs, neither cast ye your pearls before swine, lest they trample them under their feet, and turn again and rend you.
Matthew 7:6.

Anonymous at Mon, 14 Oct 2024 08:07:56 UTC No. 16430474

>>16430386
Velocity is NOT what's important here MORON. SPEED is. If a photon in-between being absorbed by atoms (Yes that is PARTICLE behavior NOT wave) suddenly decides:
>"Wow this empty space between atoms is like sooo different from the empty space between atoms in vacuum I'm gonna slow down haha just because haha sloow down XDDDD"
then Einstein was WRONG.

Anonymous at Mon, 14 Oct 2024 08:16:09 UTC No. 16430481

>>16430474
Momentum is a vector. Conservation of momentum is about conservation of a vector quantity. That’s all. Very simple to understand for someone who has a basic knowledge of physics instead of seething about a topic they have no expertise in.

Anonymous at Mon, 14 Oct 2024 08:18:03 UTC No. 16430485

>>16430481
Yep continue ignoring the problem so you can pretend you are not weong, and do leep shitting out poorly re-iterared textbook npc replies

Anonymous at Mon, 14 Oct 2024 08:23:00 UTC No. 16430493

>>16430485
you’re a funny retard. I like you. Have a cat.

Anonymous at Mon, 14 Oct 2024 08:25:57 UTC No. 16430494

I suggest you "light slows down" gorillas read this
https://www.photonics.com/Article.aspx?AID=28520

Anonymous at Mon, 14 Oct 2024 08:48:51 UTC No. 16430522

>>16424552
Phase Velocity != Group Velocity

Photons, these little wave packets/enveloped local disturbances in the EM field, travel at group velocity. The group velocity can not exceed the speed of light, or otherwise light would move faster than itself, but the phase velocity can.
Thats why you can have materials with refractive index < 1.

The anons arguing that there is a net wave travelling through the medium at a velocity less than the speed of light also conveniently forget to mention that the only way this net wave can exist is if there is indeed a wave travelling at the speed of light going through it, which can destructively interfere with the waves induced by what is affected by the photon to begin with, like charged particles and magnetic dipoles.
That is why the slowdown is merely apparent, not true.

Anonymous at Mon, 14 Oct 2024 09:47:32 UTC No. 16430579

>>16424879
this doesnt disprove what i said though

Anonymous at Mon, 14 Oct 2024 09:51:51 UTC No. 16430587

It's likr when lowbrow gorillas argue that a photon is an infinite sum of infinitely spanning plane waves which have eiisted forever infinitely far into the past and future

nigga u have brainrot

Anonymous at Mon, 14 Oct 2024 09:52:36 UTC No. 16430588

>>16430472
True.
>>16430474
Well, to be fair, the "empty space" is different because of electric fields.

Anonymous at Mon, 14 Oct 2024 10:48:27 UTC No. 16430644

>>16430588
Irrelevant. A photon entering this lattice of atoms will travel through every possible path at the same time, like the double slit experiment, and interfere with itself. The resultant superposition appears delayed coming out the other side.

What do you expect to see if you were to detect the photon at any one of these possible paths? Would it be magically slowed down here as well?

Anonymous at Mon, 14 Oct 2024 10:56:09 UTC No. 16430649

>retards ITT think polaritons are the same as photons

Anonymous at Mon, 14 Oct 2024 14:17:40 UTC No. 16430924

>>16430588
There are electrix fields in space ans tge photon still goes at the speed of light. You think I slow down time when I turn on a lamp in my room?

Anonymous at Mon, 14 Oct 2024 21:52:42 UTC No. 16431906

What's even going on here?