New magnetic component discovered in the Faraday effect
166 points
4 days ago
| 6 comments
| phys.org
| HN
namanyayg
12 hours ago
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We intuitively think in particles and see a world of billiard balls colliding with one another.

But actually everything is merely waves and fields.

There's going to be a time where humans finally reconcile the quantum with the newtonian -- and I can't wait for that day

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canjobear
10 hours ago
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There's no problem reconciling the quantum with the Newtonian. Quantum mechanics recovers Newtonian mechanics in the appropriate limit. The problem is reconciling the quantum and the Einsteinian.
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sosodev
10 hours ago
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But there’s no quantum explanation of gravity, right?
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tsimionescu
6 hours ago
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Actually, Newtonian gravity can be added to QM and work perfectly well. It's GR gravity that doesn't work with QM, especially if you try to model very high curvature like you'd get near a black hole.
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rhdunn
6 hours ago
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Quantum Electro-Dynamics (QED) is the application of Special Relativity (non-accelerating frames of reference, i.e. moving at a constant speed) to Electromagnetism. Thus, the issue is with applying accelerating frames of reference (the General in GR) to QM.
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lmpdev
10 hours ago
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At this point we have several

They’re all largely untestable though

String theory, LQG, half a dozen others

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fnordpiglet
7 hours ago
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There’s no explanation of gravity, quantum or no. There are merely descriptions.
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isolli
6 hours ago
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Isn't everything descriptions, in the end, aka models? Turtles all the way down...
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arthurcolle
10 hours ago
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Classified
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hliyan
10 hours ago
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I think neither analogy is correct. We're using macro metaphors (real world things at human time and spatial scales) to explain microscopic phenomena that may not correspond to anything that we find familiar.
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setopt
5 hours ago
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I agree with this. As a physicist, I believe the most accurate resolution is to say that «quantum fields» and «quantum particles» describe neither waves (in the sense of e.g. water or acoustic waves) nor particles (in the sense of marbles and billiard balls), but a third thing that simply has some things in common with both classical waves and classical particles. The analogies are useful for understanding that third thing, but if you believe the analogies too literally, then you’ll make mistakes.
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jagged-chisel
11 hours ago
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That we're just collections of wave interference is wild.
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isolli
6 hours ago
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We're built on so many layers of emergence, it's wild!

quantum particles => atoms => chemistry => biochemistry => cellular life => multi-cellular life => intelligence

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piva00
4 hours ago
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It can keep going!

Intelligence -> societies -> technology -> ?

One has to wonder how far can emergence stretch given enough time, some kind of entropic limit probably exists but I'm just a layman, hopefully someone more knowledgeable can share if we already know a physical hard limit for emergence.

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jacquesm
2 hours ago
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I like your progression. It makes me wonder if intelligence could lead to technology absent societies.
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boyanlevchev
1 hour ago
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If we take a simple definition of technology - such as “tool” or some external inanimate thing we use as an extension of ourselves - then I think all animals on Earth that we have deemed intelligent to some degree use “technology”. Crows using sticks to pick things out holes, chimps crafting spears for hunting, dolphins wearing “hats”, octopuses building stone fortresses, etc. So I guess it’s important to define the limit of the definition of technology.
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baq
4 hours ago
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Just listen to Feynmann trying to explain why he can't explain magnetism in macro terms (e.g. https://www.youtube.com/watch?v=MO0r930Sn_8)
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K0balt
1 hour ago
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So, are you telling me that we actually-don’t- know how magnets work lol?
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baq
1 hour ago
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Not at all - but we don't know how to explain how they work using any analogy from the macro world that we intuitively understand.
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chadcmulligan
8 hours ago
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I don't have the math, but doesn't quantum field theory say this?
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gethly
6 hours ago
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Maybe think of it as binary(particles) vs analog(waves).
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thaumasiotes
12 hours ago
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> But actually everything is merely waves and fields.

The two-slit experiment says otherwise.

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farrelle25
7 hours ago
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Another interpretation of the double-slit posits a guiding 'Pilot Wave' separate from physical particles... aka DeBroglie-Bohm Theory or Bohmian Mechanics.

Apparently it's not popular among professional physicsts though John Bell investigated it a bit. Einstein had some unpublished notes in the 1920s about a "Gespensterfeld" (ghost field) that guided particles.

Born was influenced by this 'Ghost field' idea when he published his famous interpretation of the 'Wave Function' |Ψ|^2 as a probability rather than a physical field.

More info: Nonlocal and local ghost fields in quantum correlations. https://arxiv.org/abs/quant-ph/9502017

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rhdunn
6 hours ago
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Veritasium did a video on this [1] with a surface of oil to replicate the effect on a petri dish.

[1] https://www.youtube.com/watch?v=WIyTZDHuarQ

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mock-possum
6 hours ago
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Pilot wave is still my favorite - I don’t really believe it, but I like the image
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naasking
42 minutes ago
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It is indeed a great way to translate classical intuitions to the quantum domain.
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FloorEgg
12 hours ago
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The way I've always thought of this is there are potentials for interactions and interactions.

Interactions act like point particles and potentials for interactions act like waves.

Arguing over the distinction is a bit like debating whether people are the things they do, or the thing that does things. There is some philosophical discussion to be had, but for the most part it doesn't really matter.

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jasonwatkinspdx
9 hours ago
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It does not. It shows that individual photons self interfere, so they cannot be idealized particles.
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dcl
9 hours ago
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Are you getting confused with the photoelectric effect experiment?
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gucci-on-fleek
12 hours ago
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Hmm? The double slit experiment definitely shows that particles are waves—weird quantum waves, but still waves.
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thaumasiotes
5 hours ago
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The two-slit experiment shows that photons behave like waves if you aren't looking at them, and that they fail to behave like waves if you are.
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layer8
1 hour ago
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Everett reconciled that. They only appear to fail to behave like waves because the observer is waves as well.
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fragmede
11 hours ago
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what happens when you only send a single photon down the line though?
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bobbylarrybobby
10 hours ago
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It still interferes with itself, and that interference affects the pattern of detections. It's as if the photon were a wave right up until the moment of detection, at which points it's forced to “particalize” and pick a spot to be located at — but it's the amplitude of the wave it was just before detection that determines where on the detection screen the photon is likely to show up. If you send many photons through one at a time, the detections (each just a point on the screen) will fill out the expected double slit pattern.
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mpyne
11 hours ago
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It's worth reading about, but it's kind of wave-like even then: https://en.wikipedia.org/wiki/Double-slit_experiment#Interfe...

It would be going too far to say it's only a wave though. It's both wave and particle.

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binary132
11 hours ago
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The way I read GGP was as contradicting the assertion that everything is just waves and not at all particles.
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ggm
10 hours ago
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I've always wondered what degree of confidence exists amongst the cogniscenti that a single photon event happened. I tend to think the criteria of measurement here would suggest the most likely outcome was a shitload more than 1 photon, and that all the "but we measured we can see one only" measurements are themselvs hedged by a bunch of belief.

That said, I do like the single photon experiment, when it's more than a thought experiment.

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danparsonson
9 hours ago
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It's a wave of probability, that interferes through the slits and then collapses into a probability of one somewhere along the wavefront at the point of detection. Whatever that means :-)
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gucci-on-fleek
9 hours ago
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As the other comments have already mentioned, it interferes with itself, so you still observe the same interference patterns [0] [1]. Which admittedly seems impossible at first, but so does the rest of quantum physics.

[0]: https://www.feynmanlectures.caltech.edu/III_01.html#Ch1-S5

[1]: https://en.wikipedia.org/wiki/Wave%E2%80%93particle_duality#...

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prmph
3 hours ago
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> Which admittedly seems impossible at first, but so does the rest of quantum physics.

AKA, miracles can happen, hehe.

I'm not trolling, this is a philosophical point I'm making.

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WJW
1 hour ago
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Depends on the definition of miracle I guess. There's all sort of unintuitive shit going on in the quantum world, but we can make it happen so reliably that it's hardly a miracle anymore. Wikipedia defines a miracle as "an event that is inexplicable by natural or scientific laws and accordingly gets attributed to some supernatural or praeternatural cause". But we understand "how" quantum mechanics quite well, even if the behavior described by the equations is not very intuitive to humans.
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rolph
11 hours ago
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do it once, it looks like one particle.

repeat the single photon launch many times, and you see a wavelike distribution of photon strikes

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ghostpepper
10 hours ago
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Obviously hindsight is 20/20 but this sentiment just reeks with comical levels of hubris

> However, the new research demonstrates that the magnetic field of light, long thought irrelevant,

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magphys
12 hours ago
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> To quantify this influence, the team applied their model to Terbium Gallium Garnet (TGG), a crystal widely used to measure the Faraday effect. They found that the magnetic field of light accounts for about 17% of the observed rotation at visible wavelengths and up to 70% in the infrared range.

Nearly 20% seems already significant, but 70%?! that's massive.

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gsf_emergency_6
10 hours ago
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Seems to be a minor typo . Paper:

>17.5% of the measured value for Terbium-Gallium-Garnet (TGG) at 800 nm, and up to 75% at 1.3 µm.

Here's what the crystal looks like

https://www.photonchinaa.com/tgg-terbium-gallium-garnet/

Here's transmission plot (UV-IR)

https://www.samaterials.com/terbium-gallium-garnet-crystal.h...

Note there's almost no effect on transmission

Relevant? https://dspace.mit.edu/handle/1721.1/51819

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nrhrjrjrjtntbt
11 hours ago
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Nice to see a graph of % magnetic priportion and log wavelength going from radio to gamma.
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CamperBob2
11 hours ago
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How did no one notice that before, and what else have they (we) missed?
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gsf_emergency_6
10 hours ago
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If I'd to guess: all that exp. characterization to-date has revealed no anomaly (See my other comment)

This team might have looked at bandstructure. or not (they didn't say, & I'd guess not)

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agentifysh
7 hours ago
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so what exciting applications can we see from this?
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geocar
7 hours ago
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We will put a box containing a little light and a magnet into every home and people will lose their goddamned minds looking at it every day
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discoutdynamite
4 hours ago
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This isnt exactly new. This is a obvious and predicted effect of ECE Theor. I'm surprised that neither the article nor any other commentor mentioned it yet.

tl;dr on ECE Theory: Gravity is a curvature of spacetime, electromagnetism is a torsion.

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prmph
2 hours ago
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From Wikipedia:

Einstein–Cartan–Evans theory or ECE theory was an attempted unified theory of physics proposed by the Welsh chemist and physicist Myron Wyn Evans ..., which claimed to unify general relativity, quantum mechanics and electromagnetism. The hypothesis was largely published ... between 2003 and 2005. Several of Evans's central claims were later shown to be mathematically incorrect and, in 2008, the new editor of Foundations of Physics, Nobel laureate Gerard't Hooft, published an editorial note effectively retracting the journal's support for the hypothesis.

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plaguna
10 hours ago
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But do they understand how magnets work?
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