6 ms·

How the physics of resonance shapes reality

66 points by dr_dshiv 5y ago

m-atoms 5y ago
If particles can be understood as resonances in a field then it’s hard for me to understand “stable” particles. What keeps them around? My mental model for resonance and waves requires some kind of constant input energy to maintain the oscillations in the field which produce the particles. What am I missing?
- evanb 5y ago
  Resonances are like vibrations on a trampoline; stable particles are more like lumps in a carpet. Usually what keeps particles stable is that they carry some quantum number(s) that is/are conserved, and no lighter combination of particles can be made with that combination.
  - kurthr 5y ago
    The observables are conserved, but I guess I always thought of the internal complex quantum states spinning away on their own.
- klyrs 5y ago
  Superconductors can theoretically produce perpetual motion: once you set up a supercurrent, it will keep going forever. The caveat being that the electrons that are to move perpetually cannot do work of any kind*. That is, the field generated by the supercurrent cannot be interacted with. Likewise, an ideal LC circuit made of superconducting material can theoretically ring forever, provided "nobody hears the sound". So, given my understanding of the physics, nature does not forbid stable perpetual resonances (though engineering constraints may forbid even microscopic perpetual resonators). * When people talk about "perpetual motion machines" they tend to want to extract energy from them. That's folly.
  - cout 5y ago
    Is that assuming that the superconductor itself does not undergo particle decay, or is there something special about superconductors that make them unusually stable compared to other matter in the universe?
    - klyrs 5y ago
      Yeah, I don't know jack about nuclear physics, so I drew an analogy to a field that I'm more comfortable reasoning about, the electromagnetic field.
- kurthr 5y ago
  Part of the difficulty in that analogy is that we normally think of things as damped by some surrounding media. For particles (modeled as field resonances storing quantized spatially concentrated energy) the only damping is coupling to other resonances (e.g. other particles). The particles were created by those interactions and they be annihilated (or decay) into other particles depending on how those resonances couple. Often due to quantization, this requires multiple particles including photons to "transmute" and that combination tends to reduce the likelihood of the interaction. That's my intuition from 30 years ago, anyway.
  - m-atoms 5y ago
    This was the most helpful for me, thanks!
- bsder 5y ago
  > My mental model for resonance and waves requires some kind of constant input energy to maintain the oscillations in the field which produce the particles. Your intuition is inverted from reality. Quantum mechanics dictates that a harmonic oscillator in a state will remain oscillating in that state indefinitely unless perturbed. This has the counterintuitive effect that an atom with an electron in an excited state will remain there indefinitely if you can cut off the atom from external interactions. This was, in fact, one of the arguments that Bohr used against Einstein. Experimentally--atoms decay--there is no denying that. However, Einstein's formulations said that atoms should not decay without external influence. It turns out--Einstein was right. However, those kinds experiments require things like laser traps that were far beyond the capabilities of the time.
nyc111 5y ago
"Such a bump is the unmistakable signature of “resonance,” one of the most ubiquitous phenomena in nature." If so then, physicists call "resonance" a "particle". Or what physicists call particles are resonances. But why? If you observe resonance call it resonance. I don't get it.
- wanda 5y ago
  var particle = new Resonance(); as for why, probably so that literature written now still makes sense following on from older material from the 20th century that isn't wrong but does include some antiquated terminology. Pedagogically useful to use the word particle.
- p_noumenon 5y ago
  It's still called a particle because that's a useful abstraction, and also keep in mind that correctly identifying it as resonance happened much later than people first started to use said abstraction. In reality, we know by now that there's no such thing as a particle: https://arxiv.org/abs/0807.3930 https://arxiv.org/abs/0807.3930
  - dr_dshiv 5y ago
    At first, resonance was used as a programmatic analogy to guide understanding of spectral lines. Then, it turned out that resonance wasn't a metaphor, it was a mechanism.
- blueprint 5y ago
  Particles don't really exist - they're merely what it looks like when we make a measurement of a field.
papavancato 5y ago
Very interesting!
dr_dshiv 5y ago
"Resonance underlies aspects of the world as diverse as music, nuclear fusion in dying stars, and even the very existence of subatomic particles." I learned recently that the harmonics of consonant musical notes have aligned frequencies. Meaning: the most consonant notes produce the most resonance between the strings. For example, two strings at a consonant interval of a fifth (3:2) have harmonic resonance every 3rd and every 2nd harmonic band. This is much easier to show with a visual of the spectrograms: https://docs.google.com/presentation/d/1cdRfvPtek44rH8k2GpMVnuUDsxVGC3M9ZLPt0xf5_jU/edit?usp=drivesdk https://docs.google.com/presentation/d/1cdRfvPtek44rH8k2GpMV... As oscillations of neurons in the brain will also show this harmonic structure (due to the frequency following responses [1]), consonant notes may also produce the most neural resonance! But, we don't have the ability to measure and test this hypothesis yet. [1] Bidelman, G. M., & Momtaz, S. (2021). Subcortical rather than cortical sources of the frequency-following response (FFR) relate to speech-in-noise perception in normal-hearing listeners. Neuroscience Letters, 746, 135664.
- systemsignal 5y ago
  Why would we not have ability? Is it not in the same area where implants typically are? Could try in primates potentially too
- _moof 5y ago
  This gets a little more complicated when you discover that not all fifths are the same interval, as any string player will attest. Violinists playing double stops have to use ever-so-slightly different finger positions than they do when playing single notes. And instruments with fixed tuning like pianos use something called "equal temperament," which isn't quite the 3:2 perfect fifth.
  - powersnail 5y ago
    Perfect fifths are a bitch to play on the violin indeed. You need to cover two strings with one finger, which needs to be placed at just the right angle. And it's very obvious when you are slightly out of tune, unlike single notes. But pianos don't exactly use equal temperament, either. There's a curve applied to equal temperament, which makes everything sounds more in tune. At the end of the day, musicians follow their ears. Whatever sounds the best is the most important.
motohagiography 5y ago
This rabbit hole is part of why I got into eurorack/modular. It was to apply my musical ear to intuitions to help learn about waves and harmonics. There is a lot of woo around that crossover, but when I can hear the difference in a transform and then see it reflected on an oscilloscope or in a spectrogram, its easier to get a feel for what the constants and coefficients are supposed to do. (especially with the Maths module) A generation of kids playing with their parents' rigs and getting that feel may yield a new renaissance in physics in a couple of short decades. I'm just a hacker and a writer, and beneath what might be called an artist, but I have the sense that an emerging trend of popular quantitative culture is building momentum.
peterburkimsher 5y ago
Does resonance work at other scales too? Say, perhaps, an audience waving their hands to the beat of the music? The muscle movements would then require pressure from the heart, which begins to beat synchronously as well. Also, what about very small respiratory particles; could they be resonated and "dance themselves to pieces" by using light or sound at the right wavelength?
programmarchy 5y ago
I had a weird idea related to this about 3D “shaping” massive structures in outer space. So, say you go and mine an asteroid, then put a bunch of metal into a giant “box” for lack of a better word. Then say you could tap into a large energy source from a star. Could you emit energy waves into this box that causes the metal to form itself into a certain shape? I’m thinking of those videos where they put grains of sand on a surface and vibrate it at different frequencies to produce varying shapes. With the right interference patterns, could you 3D form a spaceship hull inside the giant box full of metal floating in space?
akomtu 5y ago
At the root of reality there's some "wavy" equation that propagates changes at a certain speed (of light). The exact form of the equation is of little significance, only its "waviness" matters. This waviness is often called causality. Such equation in a confined area, any area, always and necessarily has many repetitive modes where the original state repeats itself after a certain interval, but all thosr modes exist in abstract, i.e. potentially. An external driving force allows to select one of those modes. This is probably a tautology, but maybe someone will find it interesting.

66 points by dr_dshiv 5y ago

If particles can be understood as resonances in a field then it’s hard for me to understand “stable” particles. What keeps them around? My mental model for resonance and waves requires some kind of constant input energy to maintain the oscillations in the field which produce the particles. What am I missing?

evanb 5y ago
Resonances are like vibrations on a trampoline; stable particles are more like lumps in a carpet. Usually what keeps particles stable is that they carry some quantum number(s) that is/are conserved, and no lighter combination of particles can be made with that combination.
- kurthr 5y ago
  The observables are conserved, but I guess I always thought of the internal complex quantum states spinning away on their own.
klyrs 5y ago
Superconductors can theoretically produce perpetual motion: once you set up a supercurrent, it will keep going forever. The caveat being that the electrons that are to move perpetually cannot do work of any kind*. That is, the field generated by the supercurrent cannot be interacted with. Likewise, an ideal LC circuit made of superconducting material can theoretically ring forever, provided "nobody hears the sound". So, given my understanding of the physics, nature does not forbid stable perpetual resonances (though engineering constraints may forbid even microscopic perpetual resonators). * When people talk about "perpetual motion machines" they tend to want to extract energy from them. That's folly.
- cout 5y ago
  Is that assuming that the superconductor itself does not undergo particle decay, or is there something special about superconductors that make them unusually stable compared to other matter in the universe?
  - klyrs 5y ago
    Yeah, I don't know jack about nuclear physics, so I drew an analogy to a field that I'm more comfortable reasoning about, the electromagnetic field.
kurthr 5y ago
Part of the difficulty in that analogy is that we normally think of things as damped by some surrounding media. For particles (modeled as field resonances storing quantized spatially concentrated energy) the only damping is coupling to other resonances (e.g. other particles). The particles were created by those interactions and they be annihilated (or decay) into other particles depending on how those resonances couple. Often due to quantization, this requires multiple particles including photons to "transmute" and that combination tends to reduce the likelihood of the interaction. That's my intuition from 30 years ago, anyway.
- m-atoms 5y ago
  This was the most helpful for me, thanks!
bsder 5y ago
> My mental model for resonance and waves requires some kind of constant input energy to maintain the oscillations in the field which produce the particles. Your intuition is inverted from reality. Quantum mechanics dictates that a harmonic oscillator in a state will remain oscillating in that state indefinitely unless perturbed. This has the counterintuitive effect that an atom with an electron in an excited state will remain there indefinitely if you can cut off the atom from external interactions. This was, in fact, one of the arguments that Bohr used against Einstein. Experimentally--atoms decay--there is no denying that. However, Einstein's formulations said that atoms should not decay without external influence. It turns out--Einstein was right. However, those kinds experiments require things like laser traps that were far beyond the capabilities of the time.

nyc111 5y ago

"Such a bump is the unmistakable signature of “resonance,” one of the most ubiquitous phenomena in nature." If so then, physicists call "resonance" a "particle". Or what physicists call particles are resonances. But why? If you observe resonance call it resonance. I don't get it.

wanda 5y ago
var particle = new Resonance(); as for why, probably so that literature written now still makes sense following on from older material from the 20th century that isn't wrong but does include some antiquated terminology. Pedagogically useful to use the word particle.
p_noumenon 5y ago
It's still called a particle because that's a useful abstraction, and also keep in mind that correctly identifying it as resonance happened much later than people first started to use said abstraction. In reality, we know by now that there's no such thing as a particle: https://arxiv.org/abs/0807.3930 https://arxiv.org/abs/0807.3930
- dr_dshiv 5y ago
  At first, resonance was used as a programmatic analogy to guide understanding of spectral lines. Then, it turned out that resonance wasn't a metaphor, it was a mechanism.
blueprint 5y ago
Particles don't really exist - they're merely what it looks like when we make a measurement of a field.

papavancato 5y ago

Very interesting!

dr_dshiv 5y ago

"Resonance underlies aspects of the world as diverse as music, nuclear fusion in dying stars, and even the very existence of subatomic particles." I learned recently that the harmonics of consonant musical notes have aligned frequencies. Meaning: the most consonant notes produce the most resonance between the strings. For example, two strings at a consonant interval of a fifth (3:2) have harmonic resonance every 3rd and every 2nd harmonic band. This is much easier to show with a visual of the spectrograms: https://docs.google.com/presentation/d/1cdRfvPtek44rH8k2GpMVnuUDsxVGC3M9ZLPt0xf5_jU/edit?usp=drivesdk https://docs.google.com/presentation/d/1cdRfvPtek44rH8k2GpMV... As oscillations of neurons in the brain will also show this harmonic structure (due to the frequency following responses [1]), consonant notes may also produce the most neural resonance! But, we don't have the ability to measure and test this hypothesis yet. [1] Bidelman, G. M., & Momtaz, S. (2021). Subcortical rather than cortical sources of the frequency-following response (FFR) relate to speech-in-noise perception in normal-hearing listeners. Neuroscience Letters, 746, 135664.

systemsignal 5y ago
Why would we not have ability? Is it not in the same area where implants typically are? Could try in primates potentially too
_moof 5y ago
This gets a little more complicated when you discover that not all fifths are the same interval, as any string player will attest. Violinists playing double stops have to use ever-so-slightly different finger positions than they do when playing single notes. And instruments with fixed tuning like pianos use something called "equal temperament," which isn't quite the 3:2 perfect fifth.
- powersnail 5y ago
  Perfect fifths are a bitch to play on the violin indeed. You need to cover two strings with one finger, which needs to be placed at just the right angle. And it's very obvious when you are slightly out of tune, unlike single notes. But pianos don't exactly use equal temperament, either. There's a curve applied to equal temperament, which makes everything sounds more in tune. At the end of the day, musicians follow their ears. Whatever sounds the best is the most important.

motohagiography 5y ago

This rabbit hole is part of why I got into eurorack/modular. It was to apply my musical ear to intuitions to help learn about waves and harmonics. There is a lot of woo around that crossover, but when I can hear the difference in a transform and then see it reflected on an oscilloscope or in a spectrogram, its easier to get a feel for what the constants and coefficients are supposed to do. (especially with the Maths module) A generation of kids playing with their parents' rigs and getting that feel may yield a new renaissance in physics in a couple of short decades. I'm just a hacker and a writer, and beneath what might be called an artist, but I have the sense that an emerging trend of popular quantitative culture is building momentum.

peterburkimsher 5y ago

Does resonance work at other scales too? Say, perhaps, an audience waving their hands to the beat of the music? The muscle movements would then require pressure from the heart, which begins to beat synchronously as well. Also, what about very small respiratory particles; could they be resonated and "dance themselves to pieces" by using light or sound at the right wavelength?

programmarchy 5y ago

I had a weird idea related to this about 3D “shaping” massive structures in outer space. So, say you go and mine an asteroid, then put a bunch of metal into a giant “box” for lack of a better word. Then say you could tap into a large energy source from a star. Could you emit energy waves into this box that causes the metal to form itself into a certain shape? I’m thinking of those videos where they put grains of sand on a surface and vibrate it at different frequencies to produce varying shapes. With the right interference patterns, could you 3D form a spaceship hull inside the giant box full of metal floating in space?

akomtu 5y ago

At the root of reality there's some "wavy" equation that propagates changes at a certain speed (of light). The exact form of the equation is of little significance, only its "waviness" matters. This waviness is often called causality. Such equation in a confined area, any area, always and necessarily has many repetitive modes where the original state repeats itself after a certain interval, but all thosr modes exist in abstract, i.e. potentially. An external driving force allows to select one of those modes. This is probably a tautology, but maybe someone will find it interesting.