# Is it fair to say quantum physics is essentially classical physics but when applied to microscopic scales?

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• A lot of the calculations in quantum mechanics are done using classical wave equations. The probability of an interaction occurring at a point is determined by the amplitude of the wave. The uncertainty principle is a property of a wave packet (one of finite length). The orbitals of an electron in an atom are resonant 3D standing waves.

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• No. F = ma does not apply

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• No, absolutely not.

Quantum physics is entirely different than classical physics. Objects are both particles and waves. Things don't have a position and momentum unless its being measured. Only the probability of events can be known. Quanities like energy or angular momentum come in only discrete bunndles. Objects can be in two places at the same time.

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• There is no comparison between the classical physics and quantum physics. Quantum physics has no term called as the amplitude. Classical physics has no place for wave function, Classical physics has nothing like quantum numbers and probability.

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• In the same way as saying that a speck of dust is merely a planet on a microscopic scale?

When you alter a scale dramatically there is no reason to expect that the behaviour is exactly like that at a different scale.

So it is not fair to make the statement you have given us.

It becomes a misleading extrapolation and not very useful.

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• No. At SUBATOMIC quark scales of size things become probabilistic. God DOES play dice with the Universe. Or the Force does. F does NOT equal ma. Gravity is irrelevant. The strong and weak nuclear forces predominate.

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• Absolutely not.

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• Eh it's a bit more than that. We can apply classic physics to microscopic scales. We do it all the time.

For example, when we are determining the Zeeman Effect we are simply using E = hF, a deterministic eqn, to find photon frequency F when some level of energy E is absorbed by electrons in a shell. And photons are about as microscopic as one can get.

The Zeeman results are not considered QM because the results we get, the frequency, are deterministic. There is no uncertainty in those values. When electrons jump to a higher energy level by absorbing photon energy, there will be a spectrometer line of absorption at that frequency...not a bit more, not a bit less. It's deterministic.

Quantum physics is more about what we measure, the observables, and how we interpret the physical processes, based on those observations. And because we can only measure what we can detect (observe) there is some uncertainty in the process that is creating that observable. It's that uncertainty, like the Heisenberg Uncertainty Principle, that is the hallmark of quantum physics.

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• Definitely not. Quantum physics has a whole load of effects and theories which have absolutely no counterpart in classical physics.

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If you want to formulate it that way, i.e. apply quantum physics on a macroscopic scale, then you can say that classical physics is a special case of quantum physics, same as Newtonian mechanics is a special case of General Relativity. But just because one encompasses the other doesn't mean it's the same thing.

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