Comment on Gravity
WolfLink@sh.itjust.works 3 weeks agoFundamental means it cannot be explained by being caused by something else.
Fundamental force means we expect a carrier particle to explain it (for gravity that’s the Graviton, although it hasn’t been detected yet).
electromagnetism is caused by quantum phenomena.
Not even remotely true.
What is the cause for spacetime or quantummechanics? Idk but somehow they don’t make it on the list of fundamental forces.
Quantum mechanics is mostly that statistics is more complicated than we all thought . Seeking a cause for spacetime is interesting. It might be relevant to mention that there is a fundamental particle that imparts mass, which we call the Higgs Boson. I guess that could make mass and inertia something of a “fundamental force”.
webghost0101@sopuli.xyz 3 weeks ago
Maybe i am wording it wrong. I did make the comment half joking but my current understanding of how magnetism really works, which my physics teacher was unable to answer has a chapter on wikipedia called Quantum-mechanical origin of magnetism
I have no degrees in this stuff though, i just think about them recreationally.
cynar@lemmy.world 3 weeks ago
Quantum mechanical particles are very different things to classical ones.
A slightly better way of thinking about them is quantised fields. Particles and waves are simplifications of the underlying effect. There is no classical equivalent to work with to this, so we try and understand it as particle-wave duality etc.
In this case, a carrier particle is a (quantised) disturbance in the underlying field. If it has enough energy, it manifests as a physical particle. The higgs boson is an example of this. Below the required energy, you get virtual particles. These “borrow” energy, and so can never be seen directly, only inferred.
By example. Photons are the carrier particle of electromagnetism. Give the field energy and you get photons (light). Without that energy, the photons are virtual. Existing only between the 2 acting entities.
Different fields have different carrier particles. The photon is quite simple. It’s effectiveness decays as 1/r^2 . The strong force carriers are more complex. They can emit more carrier particles, allowing the field to grow with distance rather than decay.
To add more complexity. The various fields look to be aspects of the same field. At sufficient energies, they behave identically. We have figured out how to combine the electric, magnetic and weak fields. We have a handle on the strong field. The higgs field seems to also match into this. Gravity is a pain to study. We assume it should match in, but haven’t managed to work out how yet.
As for why the underlying field exists and follows the rules it does? We have no clue right now. The ‘why’ tends to follow the ‘what’, and we have yet to get a good handle on the ‘what’.
pcalau12i@lemmygrad.ml 2 weeks ago
Arguably, if we insist on trying to come up with the simplest way to explain non-relativistic quantum mechanics, that is to say, if we are very conservative and stick to classical explanations unless we absolutely are forced not to (rather than throwing our hands up and saying it’s all magic that’s impossible to understand, as most people do), then we find that it comes naturally to explain non-relativistic quantum mechanics by treating particles as excitations in a classical field. This alone can explain the interference-based paradoxes in completely classical terms, like double-slit or Elitzur-Vaidman paradox. The extension to quantum field theory then becomes rather natural and intuitive. imo
WolfLink@sh.itjust.works 3 weeks ago
The magnetic properties of certain materials (e.g. why an unmagnetized piece of iron sticks to a magnet of either polarization), the way permanent magnets work, is best explained by quantum mechanics.
However, the electromagnetic force itself doesn’t “arise” from quantum mechanics, and you can explain things like electromagnets quite will without considering quantum mechanics.
Usually you take the “classical” formula for a force and to inform your quantum mechanical model of particles, and that’s how you can arrive at things like deriving how permanent magnets work with the help of w quantum mechanics.
Generally, a lot of material science and chemistry is inherently quantum mechanical because the way atomic orbitals and molecular bonds work is heavily quantum mechanical.
webghost0101@sopuli.xyz 3 weeks ago
Thanks for a we written reply.
Though i still dont quite get this
You seen to say if we can explain x without y then y cannot be fundamental to x.
But can electromagnetism at all emerge if the quantum mechanics dont exist to emerge things like magnetism and some of the behavior of electrons?
WolfLink@sh.itjust.works 2 weeks ago
Short answer: yes.
Technically the world can’t exist without all of its physics. But that’s kinda backwards from how you study it. Quantum mechanics isn’t “more correct” than classical mechanics, it’s more that it’s “more detailed”.
If you want to model an electromagnet, an electronic circuit, light (in most macroscopic situations), how permanent magnets interact, electrostatic situations like how static electricity makes your hair stand up, lightning, the magnetic fields of celestial bodies like the Earth and Sun (they are big electromagnets), etc. you will use “classical” electromagnetism (meaning Newton’s mechanics, possibly with Einstein’s modifications, and Maxwell’s equations).
If you want to model material science situations, like determining what material to make a diode or transistor out of, or if a given material can become a permanent magnet, you will likely need quantum mechanics to help model the interactions of electrons on the atomic scale. The section on Wikipedia you were looking at is about this kind of material science. You do this by combining the same “classical electromagnetic” equations with Schrödinger’s equations for quantum mechanics.
Zink@programming.dev 3 weeks ago
Well yeah, sure. Earlier you said something like “electromagentism is caused by quantum phenomena,” but you can say that about almost every object and behavior in the universe! We don’t have a theory of everything but the standard model and quantum field theory explain a lot.