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Just because two phenomena are described by similar equations doesn't mean they are driven by the same physical mechanism. Wave equations are ubiquitous in phy

by lisper 3y ago

Just because two phenomena are described by similar equations doesn't mean they are driven by the same physical mechanism. Wave equations are ubiquitous in physics. Sound waves. Water waves. There is no connection between any of these and QM.

akasakahakada 3y ago
So wave function is not a part of QM?
- sidlls 3y ago
  It’s more that wave functions are ubiquitous in all areas of physics. It generally falls out of the fact that we can model tons of stuff with second order differential equations, which often result in models that have oscillator/wave-like behaviors
- mannykannot 3y ago
  You are mixing up two different (but related) terms. The wave equation is a second-order partial differential equation which has some solutions in the form of waves. A QM wave function is a particular case of a wave equation, yielding a probability amplitude. One significant application of the wave equation in pre-quantum physics occurred when Maxwell was able to derive, from the electromagnetic theory he was developing, a wave equation having solutions in which electromagnetic waves propagate at the speed of light.
aeternum 3y ago
First order differential equations generally govern diffusion where energy spreads out over an area. Second order are often waves where energy propagates but does not diffuse. Is pretty much everything described by those two classes? Any third-order differential equations in physics?
- defrost 3y ago
  Good question. First & second order covers most cases, third order applications include things with 'jerk', sticky flows through small channels, .. There are other examples offered here: https://www.researchgate.net/post/Are_there_examples_of_third-order_linear_differential_equations_in_physics_or_applied_mathematics https://www.researchgate.net/post/Are_there_examples_of_thir... https://www.quora.com/Why-dont-differential-equations-of-physics-go-beyond-the-second-order https://www.quora.com/Why-dont-differential-equations-of-phy... https://math.stackexchange.com/questions/2167292/are-there-examples-of-third-or-higher-order-linear-differential-equations-in-p https://math.stackexchange.com/questions/2167292/are-there-e...
pbir 3y ago
This is a big beef I have with a lot of STEM types, especially in IT Math should never be taken a concrete thing. It’s a guide to understanding such things. A map. Truth in the physical world is determined by experiment. That’s physics. Too many in IT and engineering seem to think making purpose built counting machine count is experimental verification. We can’t iterate on rockets forever; not enough stuff. Yet so many smart people just scoff at the idea. Unscientific mind viruses about reality for us being endless permeate society. Even as religion fades, paranoia at the real nature of reality, anxiety over it, has latched on to the biology religion accidentally stumbled upon.
3cats-in-a-coat 3y ago
If phenomena are described by similar equations, it does mean that there’s something in common between them. For example the equations :). The equations are a system of constraints. Means both systems are constrained in the same way. And we cannot simply hand wave this away and say it’s just a coincidence. A system of coincidences. We need to at least try to figure out why is that, before we dismiss it so haphazardly.
- lisper 3y ago
  > We need to at least try to figure out why is that, before we dismiss it so haphazardly. No, we don't. There is enough misinformation and woo surrounding QM already. There is absolutely no reason to entertain the notion that there is some deep connection between QM and any macroscopic phenomenon simply because both inolve a wave equation. That's just stupid.
  - futurisold 3y ago
    > There is enough misinformation and woo surrounding QM already. There is absolutely no reason to entertain the notion that there is some deep connection between QM and any macroscopic phenomenon simply because both involve a wave equation. I'm with you here. Lot of ground for certain people to pick the sentence and use it out of context to augment their systematic bullshit.
    - 3cats-in-a-coat 3y ago
      Would you suppress actual scientific discovery if it happens to be similar to some "woo" a scammer used in his cult? Is this how you weigh things... better to ignore truth than admit some fake science has merit, even if by accident? This is not a description of the scientific process, but a description of tribalism, polarization and confirmation bias. People who prefer their team to end up right (or even worse, their goal is for the other team to end up wrong regardless of merit) by bending reality to fit their view, rather than bend themselves to perceive reality as it is, end up wrong. Things tend to fall into patterns in physics, chemistry, ecosystems, societies, information technology. If they didn't, math would be useless, as it's the abstract description of such patterns and the quantitative relationships of measurable variables within them. And these patterns will be constantly rediscovered, often by different people, under different names, with different levels of sophistication, and many of those people won't have the best of intentions or wisdom how to use what they found, or guessed about. We can't simply reject every concept, simpy because someone we don't like happens to subscribe to it. This is an outright childish way of looking at the world.
ElMocambo_x4 3y ago
I realized I asked a similar question but then let's put it another way: would it be problematic if in reverse, some quantic phenomenons were found to be described well by Newtonian equations ?
- lisper 3y ago
  This wouldn't be "problematic", it's just extremely unlikely to happen. The math of QM is fully understood. No experiment in over 50 years has produced results incompatible with QM. (This has produced a major crisis in physics.) Some aspects of the math of QM -- the ones that produce the "quantum weirdness" that gets everyone's attention -- are fundamentally incompatible with the math of classical mechanics. CM is local, QM is non-local. Locality is intuitive, non-locality is not. So the odds of discovering something fundamentally new in QM at all, let alone something that can be described by the math of CM, are indistinguishable from zero. There are some aspects of our day-to-day lives that are governed by QM, like rainbows and transistors. But not weather or climate. Those are purely classical phenomena.

by lisper 3y ago

akasakahakada 3y ago

So wave function is not a part of QM?

sidlls 3y ago
It’s more that wave functions are ubiquitous in all areas of physics. It generally falls out of the fact that we can model tons of stuff with second order differential equations, which often result in models that have oscillator/wave-like behaviors
mannykannot 3y ago
You are mixing up two different (but related) terms. The wave equation is a second-order partial differential equation which has some solutions in the form of waves. A QM wave function is a particular case of a wave equation, yielding a probability amplitude. One significant application of the wave equation in pre-quantum physics occurred when Maxwell was able to derive, from the electromagnetic theory he was developing, a wave equation having solutions in which electromagnetic waves propagate at the speed of light.

aeternum 3y ago

First order differential equations generally govern diffusion where energy spreads out over an area. Second order are often waves where energy propagates but does not diffuse. Is pretty much everything described by those two classes? Any third-order differential equations in physics?

defrost 3y ago
Good question. First & second order covers most cases, third order applications include things with 'jerk', sticky flows through small channels, .. There are other examples offered here: https://www.researchgate.net/post/Are_there_examples_of_third-order_linear_differential_equations_in_physics_or_applied_mathematics https://www.researchgate.net/post/Are_there_examples_of_thir... https://www.quora.com/Why-dont-differential-equations-of-physics-go-beyond-the-second-order https://www.quora.com/Why-dont-differential-equations-of-phy... https://math.stackexchange.com/questions/2167292/are-there-examples-of-third-or-higher-order-linear-differential-equations-in-p https://math.stackexchange.com/questions/2167292/are-there-e...

pbir 3y ago

This is a big beef I have with a lot of STEM types, especially in IT Math should never be taken a concrete thing. It’s a guide to understanding such things. A map. Truth in the physical world is determined by experiment. That’s physics. Too many in IT and engineering seem to think making purpose built counting machine count is experimental verification. We can’t iterate on rockets forever; not enough stuff. Yet so many smart people just scoff at the idea. Unscientific mind viruses about reality for us being endless permeate society. Even as religion fades, paranoia at the real nature of reality, anxiety over it, has latched on to the biology religion accidentally stumbled upon.

3cats-in-a-coat 3y ago

If phenomena are described by similar equations, it does mean that there’s something in common between them. For example the equations :). The equations are a system of constraints. Means both systems are constrained in the same way. And we cannot simply hand wave this away and say it’s just a coincidence. A system of coincidences. We need to at least try to figure out why is that, before we dismiss it so haphazardly.

lisper 3y ago
> We need to at least try to figure out why is that, before we dismiss it so haphazardly. No, we don't. There is enough misinformation and woo surrounding QM already. There is absolutely no reason to entertain the notion that there is some deep connection between QM and any macroscopic phenomenon simply because both inolve a wave equation. That's just stupid.
- futurisold 3y ago
  > There is enough misinformation and woo surrounding QM already. There is absolutely no reason to entertain the notion that there is some deep connection between QM and any macroscopic phenomenon simply because both involve a wave equation. I'm with you here. Lot of ground for certain people to pick the sentence and use it out of context to augment their systematic bullshit.
  - 3cats-in-a-coat 3y ago
    Would you suppress actual scientific discovery if it happens to be similar to some "woo" a scammer used in his cult? Is this how you weigh things... better to ignore truth than admit some fake science has merit, even if by accident? This is not a description of the scientific process, but a description of tribalism, polarization and confirmation bias. People who prefer their team to end up right (or even worse, their goal is for the other team to end up wrong regardless of merit) by bending reality to fit their view, rather than bend themselves to perceive reality as it is, end up wrong. Things tend to fall into patterns in physics, chemistry, ecosystems, societies, information technology. If they didn't, math would be useless, as it's the abstract description of such patterns and the quantitative relationships of measurable variables within them. And these patterns will be constantly rediscovered, often by different people, under different names, with different levels of sophistication, and many of those people won't have the best of intentions or wisdom how to use what they found, or guessed about. We can't simply reject every concept, simpy because someone we don't like happens to subscribe to it. This is an outright childish way of looking at the world.

ElMocambo_x4 3y ago

I realized I asked a similar question but then let's put it another way: would it be problematic if in reverse, some quantic phenomenons were found to be described well by Newtonian equations ?

lisper 3y ago
This wouldn't be "problematic", it's just extremely unlikely to happen. The math of QM is fully understood. No experiment in over 50 years has produced results incompatible with QM. (This has produced a major crisis in physics.) Some aspects of the math of QM -- the ones that produce the "quantum weirdness" that gets everyone's attention -- are fundamentally incompatible with the math of classical mechanics. CM is local, QM is non-local. Locality is intuitive, non-locality is not. So the odds of discovering something fundamentally new in QM at all, let alone something that can be described by the math of CM, are indistinguishable from zero. There are some aspects of our day-to-day lives that are governed by QM, like rainbows and transistors. But not weather or climate. Those are purely classical phenomena.