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> There is really nothing quantum in this Even if you consider a Hydrogen atom floating in free space a billion miles from any planets, everything about it is

> There is really nothing quantum in this Even if you consider a Hydrogen atom floating in free space a billion miles from any planets, everything about it is 100% "quantum". There are no actual electrons going around the nucleus, because it's purely just a quantum probability wave. If you then introduce Oxygen atoms near it, then the probability wave of the two begin to behave as a single system and will oscillate in a different pattern but STILL a single quantum mechanical system, and one big "wave function" that represents the entire system. In this multi-atom system you also cannot even say that one specific electron is going around one atom, and another electron is going around a different electron (the incorrect classical view). The electron probability wave for the entire system is one big probability wave oscillator function, and both electrons contribute to magnitudes of observables in an identical way to each other. So the two electrons loose their individual identity. They're both part of a 'cloud' but you can't say where any of them are. Not because it's hard to measure, but because actually reality itself doesn't even know. None of this is inconsistent with the fact that the classical view also holds true under ordinary observational conditions, and can be estimated (albeit incorrectly) as pre-existing atoms "snapping together" by the laws of chemistry, but that is the less 'complete' view. Just like Newton is a less complete view than Relativity, but still 'works'.

tsimionescu 6y ago
While the electrons do form a cloud and aren't entirely well positioned in space as far as we know, it's important to remember that there still are a fixed number of electrons which can be detected one by one, even though they may interact with themselves or each other at multiple positions at the same time before our detection. Furthermore, it is not yet proven that reality behaves the same in classical settings as it does in quantum interactions. For all we know, wave function collapse may be a physical phenomenon that happens at specific conditions, yielding purely classical behavior. Your explanation is one popular view of QM, but it is not the only possibility that would be consistent with observations.
- WClayFerguson 6y ago
  > Your explanation is one popular view of QM If you want to call the "Standard Model" merely one among many "popular views" then you can, but that's not what I'd call accurate. No one really disagrees with it. They just have different "interpretations" of why it holds true. Regarding your claim that electrons "interact with themselves", that's actually kind of misleading too. When electrons are "in the cloud" (pre-wave-collapse) they're pure probability and so none of them have an actual location in spacetime even if you had some infinitely fast camera to look. They simply don't exist at specific locations. They are genuinely everywhere at once, or stated even more correctly: they don't exist. Only the energy exists. The "Bohr Model" of the atom is correct insofar as a way to track energies in a classically relevant way, but in no way at all is it actually "real". There's no electrons flying around. Only electrons that have already stopped. They don't exist until measured.
  - tsimionescu 6y ago
    > If you want to call the "Standard Model" merely one among many "popular views" then you can, but that's not what I'd call accurate. No one really disagrees with it. They just have different "interpretations" of why it holds true. The Standard Model doesn't contain an explanation for the measurement problem, which is essentially what your explanation is touching on, with the claim that everything is quantum and that the electron really doesn't have a definite position in space, rather than us being unable to know its position. Basically you stated a version of the Copenhagen Interpretation, which is very popular, but not the only way of making sense of the wave function. > When electrons are "in the cloud" (pre-wave-collapse) they're pure probability and so none of them have an actual location in spacetime even if you had some infinitely fast camera to look. They simply don't exist at specific locations. They are genuinely everywhere at once, or stated even more correctly: they don't exist. Only the energy exists. I think you're mixing things up a bit here. Before a measurement takes place, the movement of electrons is predicted by a deterministic equation, there is no probability. The electron is indeed (described by?) a wave function that has some amplitude at any point in space. My point about "interacting with themselves" was that the Schrodinger equation predicts the possibility of self-interference of a single electron's wave function, which is an observed effect. I think you're also over-selling the wave part of the duality and disregarding the particle part. The electron doesn't behave entirely like a wave, it also has particle-like properties, such as a fixed mass and a fixed charge. > There's no electrons flying around. Only electrons that have already stopped. They don't exist until measured. This is exactly the part that people love claiming as if it is settled, when it is anything but. The reality is that we don't yet know what quantum particles are. If they don't exist until you measure and then they start existing, then you need to explain what a measurement is, which we have no idea how to. In fact, even the Copenhagen interpretation doesn't exactly say what you are claiming. It is instead claiming that the wave function + the Born rule are a mathematical tool that predicts the behavior of quantum systems with excellent accuracy, and that the probabilities in the Born rule are fundamental. If we accept this fundamental impossibility of predicting deterministically the properties of a quantum system, it follows that it is unscientific to claim that the particles "have" properties that we fundamentally can't measure. This un-existence is then a philosophical argument, not a physical one: it's stating that something that can't in principle be measured can't be said to exist. Other popular explanations that are perfectly compatible with the Standard Model are: - the particles are real, and they exist at all positions in space as predicted by the Schrodinger equation, but these results happen in different universes; for some unexplained reason, "classical objects" can only observe one world at a time - particles are real, and their movement is affected by a real carrier wave; the particle has a definite but unmeasurable location in space and speed, affected by the carrier wave; the carrier wave is the wave described by the Schrodinger equation - Measurement is a physical process that causes particles to switch from being somewhat indefinite objects described by the wave function to being definite objects described by classical (rather, relativistic) mechanics Of course, some of these interpretations have their own unintuitive aspects (non-locality), because of the Bell inequalities. There is also super-determinism, that could in principle allow QM to be both deterministic and local, at the cost of statistical independence. And finally, the Standard Model itself doesn't yet account for gravity, and the current theories we have for gravity do not work with masses that have indefinite positions in space, so there is still room for discoveries that could contradict somewhat the fundamental properties of "particles" as known today (though, to be fair, it is more likely that our theories about gravity are the ones that will need adjustment).
gus_massa 6y ago
[Replying here as you suggested in the other comment.] The balls in a pool table are 100% quantum, but they are approximated very accurately by Classic Mechanics. At this level, the position of the nuclei can be approximated to move classically, and the electrons quantically. Moreover, the standard trick is to approximate that the nuclei doesn't move, and then calculate the distributions of the electron with quantum mechanics. https://en.wikipedia.org/wiki/Born%E2%80%93Oppenheimer_approximation https://en.wikipedia.org/wiki/Born%E2%80%93Oppenheimer_appro... Once you calculate the distribution of the electrons assuming the nuclei are at different positions, you can approximate an effective force between the nuclei and calculate how they move almost like classic objects. The calculation is too difficult, and the other nearby atoms affect them, so there are a lot of approximations. For big system, you need to use something like https://en.wikipedia.org/wiki/Born%E2%80%93Oppenheimer_approximation https://en.wikipedia.org/wiki/Born%E2%80%93Oppenheimer_appro... that approximate the force between the atoms, with some formulas that hide all the quantumness and then move as if they were classic objects. So it's a quantum system, like everything in this word. But the apparent atoms that appear and disappear are not explained by weird quantum effects. They can be explained with the simplified classic model when the camera takes too few frames, the objects are moving too much, and the background is too noisy.
- WClayFerguson 6y ago
  I'm glad we agree that classical mechanics accurately predicts macro objects. However, atoms, molecules, and even molecular lattices containing a small number of atoms (or large number actually), behave as quantum wave systems. Even the link you gave states that 'benzene' despite having 42 electrons, has a single wave function that determines probabilities for where an electron can be observed (but not WHICH electron. There is no WHICH ELECTRON in the function). In that wave function it means there's no longer 42 actual electrons that even exist. There is nothing but a probability of where you'd find one if you collapse the entire wave simultaneously by taking a measurement of any part of it. When atoms join into a crystal formation that becomes even a 'higher level' new emergent pattern of vibrating probabilities, that's more complex and structured than what the individual particles exhibited before the new pattern emerged. You think I'm wrong to say atoms pop into existence?, but we know for a fact all particles are merely probabilities until observed. All observation is synonymous with wave-collapse, and only upon wave-collapse do you have actual particles with actual positions in spacetime. Every 'frame' of every video you could ever create is a snapshot of "a series of collapses", because that collapse is what created the particles that make up the 'image' itself.
soulofmischief 6y ago
Quantum Field Theory has a lot of strong evidence, as does the Copenhagen interpretation of QM, but it might be more suitable not to speak of these things as if they are 100% fact. It's theory, and it's likely that the eventual bridge between QM and classical physics will usher in an entirely new model unlike either individual model.
- WClayFerguson 6y ago
  I always refer to QFT + Standard Model as 'fact' even though myself and all other Physicists agree there may be deeper understandings than what is currently known by science. At some point is becomes philosophy when you call into question something that has zero evidence against it and the evidence in favor of it has been measured out to 43 decimal places already.

tsimionescu 6y ago

While the electrons do form a cloud and aren't entirely well positioned in space as far as we know, it's important to remember that there still are a fixed number of electrons which can be detected one by one, even though they may interact with themselves or each other at multiple positions at the same time before our detection. Furthermore, it is not yet proven that reality behaves the same in classical settings as it does in quantum interactions. For all we know, wave function collapse may be a physical phenomenon that happens at specific conditions, yielding purely classical behavior. Your explanation is one popular view of QM, but it is not the only possibility that would be consistent with observations.

WClayFerguson 6y ago
> Your explanation is one popular view of QM If you want to call the "Standard Model" merely one among many "popular views" then you can, but that's not what I'd call accurate. No one really disagrees with it. They just have different "interpretations" of why it holds true. Regarding your claim that electrons "interact with themselves", that's actually kind of misleading too. When electrons are "in the cloud" (pre-wave-collapse) they're pure probability and so none of them have an actual location in spacetime even if you had some infinitely fast camera to look. They simply don't exist at specific locations. They are genuinely everywhere at once, or stated even more correctly: they don't exist. Only the energy exists. The "Bohr Model" of the atom is correct insofar as a way to track energies in a classically relevant way, but in no way at all is it actually "real". There's no electrons flying around. Only electrons that have already stopped. They don't exist until measured.
- tsimionescu 6y ago
  > If you want to call the "Standard Model" merely one among many "popular views" then you can, but that's not what I'd call accurate. No one really disagrees with it. They just have different "interpretations" of why it holds true. The Standard Model doesn't contain an explanation for the measurement problem, which is essentially what your explanation is touching on, with the claim that everything is quantum and that the electron really doesn't have a definite position in space, rather than us being unable to know its position. Basically you stated a version of the Copenhagen Interpretation, which is very popular, but not the only way of making sense of the wave function. > When electrons are "in the cloud" (pre-wave-collapse) they're pure probability and so none of them have an actual location in spacetime even if you had some infinitely fast camera to look. They simply don't exist at specific locations. They are genuinely everywhere at once, or stated even more correctly: they don't exist. Only the energy exists. I think you're mixing things up a bit here. Before a measurement takes place, the movement of electrons is predicted by a deterministic equation, there is no probability. The electron is indeed (described by?) a wave function that has some amplitude at any point in space. My point about "interacting with themselves" was that the Schrodinger equation predicts the possibility of self-interference of a single electron's wave function, which is an observed effect. I think you're also over-selling the wave part of the duality and disregarding the particle part. The electron doesn't behave entirely like a wave, it also has particle-like properties, such as a fixed mass and a fixed charge. > There's no electrons flying around. Only electrons that have already stopped. They don't exist until measured. This is exactly the part that people love claiming as if it is settled, when it is anything but. The reality is that we don't yet know what quantum particles are. If they don't exist until you measure and then they start existing, then you need to explain what a measurement is, which we have no idea how to. In fact, even the Copenhagen interpretation doesn't exactly say what you are claiming. It is instead claiming that the wave function + the Born rule are a mathematical tool that predicts the behavior of quantum systems with excellent accuracy, and that the probabilities in the Born rule are fundamental. If we accept this fundamental impossibility of predicting deterministically the properties of a quantum system, it follows that it is unscientific to claim that the particles "have" properties that we fundamentally can't measure. This un-existence is then a philosophical argument, not a physical one: it's stating that something that can't in principle be measured can't be said to exist. Other popular explanations that are perfectly compatible with the Standard Model are: - the particles are real, and they exist at all positions in space as predicted by the Schrodinger equation, but these results happen in different universes; for some unexplained reason, "classical objects" can only observe one world at a time - particles are real, and their movement is affected by a real carrier wave; the particle has a definite but unmeasurable location in space and speed, affected by the carrier wave; the carrier wave is the wave described by the Schrodinger equation - Measurement is a physical process that causes particles to switch from being somewhat indefinite objects described by the wave function to being definite objects described by classical (rather, relativistic) mechanics Of course, some of these interpretations have their own unintuitive aspects (non-locality), because of the Bell inequalities. There is also super-determinism, that could in principle allow QM to be both deterministic and local, at the cost of statistical independence. And finally, the Standard Model itself doesn't yet account for gravity, and the current theories we have for gravity do not work with masses that have indefinite positions in space, so there is still room for discoveries that could contradict somewhat the fundamental properties of "particles" as known today (though, to be fair, it is more likely that our theories about gravity are the ones that will need adjustment).

gus_massa 6y ago

[Replying here as you suggested in the other comment.] The balls in a pool table are 100% quantum, but they are approximated very accurately by Classic Mechanics. At this level, the position of the nuclei can be approximated to move classically, and the electrons quantically. Moreover, the standard trick is to approximate that the nuclei doesn't move, and then calculate the distributions of the electron with quantum mechanics. https://en.wikipedia.org/wiki/Born%E2%80%93Oppenheimer_approximation https://en.wikipedia.org/wiki/Born%E2%80%93Oppenheimer_appro... Once you calculate the distribution of the electrons assuming the nuclei are at different positions, you can approximate an effective force between the nuclei and calculate how they move almost like classic objects. The calculation is too difficult, and the other nearby atoms affect them, so there are a lot of approximations. For big system, you need to use something like https://en.wikipedia.org/wiki/Born%E2%80%93Oppenheimer_approximation https://en.wikipedia.org/wiki/Born%E2%80%93Oppenheimer_appro... that approximate the force between the atoms, with some formulas that hide all the quantumness and then move as if they were classic objects. So it's a quantum system, like everything in this word. But the apparent atoms that appear and disappear are not explained by weird quantum effects. They can be explained with the simplified classic model when the camera takes too few frames, the objects are moving too much, and the background is too noisy.

WClayFerguson 6y ago
I'm glad we agree that classical mechanics accurately predicts macro objects. However, atoms, molecules, and even molecular lattices containing a small number of atoms (or large number actually), behave as quantum wave systems. Even the link you gave states that 'benzene' despite having 42 electrons, has a single wave function that determines probabilities for where an electron can be observed (but not WHICH electron. There is no WHICH ELECTRON in the function). In that wave function it means there's no longer 42 actual electrons that even exist. There is nothing but a probability of where you'd find one if you collapse the entire wave simultaneously by taking a measurement of any part of it. When atoms join into a crystal formation that becomes even a 'higher level' new emergent pattern of vibrating probabilities, that's more complex and structured than what the individual particles exhibited before the new pattern emerged. You think I'm wrong to say atoms pop into existence?, but we know for a fact all particles are merely probabilities until observed. All observation is synonymous with wave-collapse, and only upon wave-collapse do you have actual particles with actual positions in spacetime. Every 'frame' of every video you could ever create is a snapshot of "a series of collapses", because that collapse is what created the particles that make up the 'image' itself.

soulofmischief 6y ago

Quantum Field Theory has a lot of strong evidence, as does the Copenhagen interpretation of QM, but it might be more suitable not to speak of these things as if they are 100% fact. It's theory, and it's likely that the eventual bridge between QM and classical physics will usher in an entirely new model unlike either individual model.

WClayFerguson 6y ago
I always refer to QFT + Standard Model as 'fact' even though myself and all other Physicists agree there may be deeper understandings than what is currently known by science. At some point is becomes philosophy when you call into question something that has zero evidence against it and the evidence in favor of it has been measured out to 43 decimal places already.