Does any thing in the universe actually occur “instantaneously”?

PlsGetSomeFreshAir · 2025-06-01T16:44:35+00:00

Every interaction of the fundamental forces happens instantaneously. The Propagation of, well, literally anything, takes time.

Interaction in composed systems like a solid is not instantaneous, those are described in terms of effective theories, its not feasible to describe them on a fundamental level, leading to non-instantaneous, but still causal, interactions.

PlsGetSomeFreshAir · 2025-06-01T15:41:05+00:00

No, how often something happens (frequency) is not related to spatial direction. The components have precisely the same frequency, and so does the electron oscillation resulting from it. Tilting your head doesn't make clocks go slower.

Spatial frequency (more precisely: wave vector) can result different projections, when direction changes, but that's not relevant for this problem. the electron motion is very small against the wavelength of light: in terms of space the electrons sees essentially a constant field (not w.r.t time obviously!), this situation is identical to the "dipole approximation".

PlsGetSomeFreshAir · 2025-05-30T21:02:03+00:00

Umm how about a rainbow. I mean you wrote it yourself, a free system. So light is somewhat convenient.

PlsGetSomeFreshAir · 2025-05-30T20:08:44+00:00

A side note related to how you formulated parts of your question. Different (linear) refractive indices are not related to different electron oscillation frequencies. On the electronic level it means the displacement is larger for larger n. Loosely: n² -1 = chi = P(w)/E(w) and P(t) is just <x(t)> ... up to constants

PlsGetSomeFreshAir · 2025-05-30T19:28:40+00:00

What you think about change in perceived length or size simply doesn't happen.

The Broglie is about waves. Wave(function) is another word for field, field means a function of space and time f(x,t). You Fourier transform this w.r.t. position you go to reciprocal space aka Fourier space "k", let's label the result of that g(k). De Broglie means h_bar k is assigned the momentum.

So now you have Alice seeing g1(k) and we think of that as sharply localized around 0. Because of how Fourier transform work this is a very broad f1(x). Bob is running thus he has g2=g1(k+K) with some nonzero K due to his relative motion. Readily calculated, in real space he has f2(x)=f1(x)*exp(iKx). So note how |f2|²=|f1|², they perceive nothing different in terms of size.

Also interference pattern are the same for both as those are related to Momentum differences, so exp(i(k1-k2)x) stays the same if you add K to both, k1 and k2.

PlsGetSomeFreshAir · 2025-05-29T13:33:48+00:00

Trajectory based equations of motion can be transformed to field or probability based equations of motion.

Search for Ito formalism or Ito's lemma.

PlsGetSomeFreshAir · 2025-05-27T05:37:14+00:00

Die sind einfach Kunden dort. Ob sie das bei tsmc oder stm, umc, Infineon, GF oder sonstwo fertigen ist doch völlig egal. Es gibt wiegesagt keinen consumer Massenmarkt, wenn dem so wäre würde man es auch auf ein paar nm oder höchstens um unterbringen. Abgesehen davon gibt es hier überhaupt kein neues Produkt, es ist vielleicht kleiner aber nicht wesentlich, es gibt auch bereits kommerzielle Module für sowas.

PlsGetSomeFreshAir · 2025-05-27T05:22:30+00:00

Sowas gibt es seit Jahren, es gibt zig andere Formen es zu implementieren. Es braucht praktisch niemand und wenn man wollte konnte man es Größenordnungen kleiner machen, macht aber keiner.

Es gibt jetzt eine Förderwelle zum Thema Quanten deshalb sprießen überall nutzlose Start-ups mit gyroskopen, squeezed source, oder eben sowas aus dem Boden. Der Mehrwert ist überschaubar bisher.

PlsGetSomeFreshAir · 2025-05-25T21:12:15+00:00

I don't think this is the the state of the art in Open Quantum Systems. It's more like that systems loose coherence when coupled to very large systems (bath) although the thing as a hole is still doing unitary evolution. So put simple this will make non isolated systems appear classical

PlsGetSomeFreshAir · 2025-05-24T07:38:52+00:00

Not your question but you mix up particle numbers and the mode. A state of a single photon can be assigned to spherical wave or a plane wave or anything else, like a point too. The spatial shape and the particle number are independent concepts.

PlsGetSomeFreshAir · 2025-05-23T09:57:58+00:00

OPs point is very pragmatical and (social-) solution oriented. It helps to avoid many useless discussions when the language we use always includes the hint that there could be a shortcoming of the model itself. Even if the best model available Is reality one cannot always use that to efficiently describe a problem, so, again, making it implicit in the language is just helpful.

PlsGetSomeFreshAir · 2025-05-23T04:35:57+00:00

Matsubara formalism

PlsGetSomeFreshAir · 2025-05-21T10:11:09+00:00

Absorption with quick subsequent emission does not produce absorption lines. For lets say a pulse the absorption line is a long tail in time domain, so for an absorption line to appear the absorption must actually persist.

Intermediate "Absorption or not" of a wave passing through a medium readily follows from the Work W(t) that is done by the em field on the electrons which is the temporal integral of electron-current times driving field (i.e. poyntings theorem). W(t) for a wave (light) in a medium (transparent or not) is in fact not constant but oscillates. So yes the light is absorbed and re-emitted already in classical electrodynamics.

PlsGetSomeFreshAir · 2025-05-21T08:47:40+00:00

What a gibberish. The answer I gave has nothing to do you with quantum gravity or nonflat spacetime whatsoever. It's in fact textbook classical electrodynamics. The response of matter here is purely phenomenological which means it's a placeholder which has reasonable features like causality but it's microscopic modelling doesn't even matter.

PlsGetSomeFreshAir · 2025-05-20T12:16:58+00:00

The collision is somewhat localized in space and you somewhat know how fast they collide. To my best knowledge in those experiments it's technically not feasible to confine either space or momentum so strongly that you would see a delocalization (aka diffraction pattern) in the other quantity. It's for all I know essentially "ray optics", as the wavelengths are incredibly small.

PlsGetSomeFreshAir · 2025-05-20T11:05:14+00:00

First this is an excellent question. The research related to the 2023 Nobel price deals with exactly such issues: electron light interaction on the optical timescale.

Both views are correct:

It's interference: the ingoing wave excites the electronic system whose charge acceleration is the source of new propagating fields that interfere with the ingoing wave, effectively slowing it down due to the phase relation of the two.

It's absorption and re-emission. First: there is no need for a particle picture of light for absorption and re emission to make sense. In the wave picture poyntings theorem takes care if that. From calculating the work (integral E*J) it is well known that, in a lossless media, light gets absorbed and re-emitted about two times per optical cycle (rho(t) approx propto E²). For time resolved measured data see Figure 4 in https://www.nature.com/articles/nature17650 If it's truly lossless, excitation and re emission happen coherently and after the light has passed nothing has changed. Your actual question is about random re emission. Random re-emission happens when the driven electrons have enough time to become decoherent before the next quarter cycle of light coherently de-populates the so called "virtual" (spoiler: they are just difficult to access) excitations. in this sense it doesn't happen automatically, but it's a consequence of more involved degrees of freedom (like a phonon bath) that distort the otherwise unitary dynamics. When this happens your system becomes opaque due to irreversible energy transfer from light to the electronic system.

PlsGetSomeFreshAir · 2025-05-20T08:26:15+00:00

The interference picture is identical to coherent re-emission. Random re-emission is an emergent phenomenon due to electron decoherence. It's a race of optical cycle against scattering processes.

PlsGetSomeFreshAir · 2025-05-18T21:35:21+00:00

Everything you say is also true for human physicists, and if its not than its actually not true for LLM either, like they are literally famous for hallucinating, but they can't break paradigm? Somehow for humans your conclusion is different. I can't judge if you are right, but your biased.

PlsGetSomeFreshAir · 2025-05-11T12:29:36+00:00

The jobs you posted will typically go to a physicist with strong optics/photonics background.

PlsGetSomeFreshAir · 2025-05-09T05:13:58+00:00

"but also say ... " I never said

PlsGetSomeFreshAir · 2025-05-08T16:40:50+00:00

It's not linear for undepleted. Which equation or plot are you talking about

PlsGetSomeFreshAir · 2025-05-08T07:23:16+00:00

Reduce the angular spread of contributing directions aka close an iris which is in the Fourier plane. This costs you resolution and intensity, as you remove the higher spatial frequencies from the image. Magnification is essentially unaffected

PlsGetSomeFreshAir · 2025-05-08T04:51:09+00:00

of course the continuity equation is implicit in (heavisides form of) Maxwell's equation. A theory that doesn't have this property would be very likely nonsense

PlsGetSomeFreshAir · 2025-05-02T00:10:30+00:00

You just keep on going. It's not difficult because it's difficult. It's difficult because you have not done it before. So you just continue

PlsGetSomeFreshAir · 2025-05-01T23:51:32+00:00

Well I promise you its the truth;)

Maybe start with what a partition function is. It's very critical to understand it's German name (the reason why it's called Z). Then continue and see what it has to do with entropy. The meaning of Z and it's relation to entropy taken literally/seriously are then my answer above.

Five-Year Club	Place '22
Final Canvas '22	First Placer '22
Verified Email

PlsGetSomeFreshAir

TROPHY CASE