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zhanhai
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Why wavefunction (the square of its modulus) of an electron is not seen as a measure of substance/charge distribution of the electron?
zhanhai said:Why wavefunction (the square of its modulus) of an electron is not seen as a measure of substance/charge distribution of the electron?
stevendaryl said:The problem with thinking of the wavefunction as a physical quantity, or field, is that it doesn't exist in space, it exists in configuration space.
What I mean by that is this: Suppose we have two particles. The wave function for that pair is a function of the form:
[itex]\Psi(x_1, y_1, z_1, x_2, y_2, z_2)[/itex]
which gives the probability amplitude for finding the first particle at [itex](x_1, y_1, z_1)[/itex] and the second particle at [itex](x_2, y_2, z_2)[/itex].
When you square it, you don't get the probability of finding anything at [itex](x_1, y_1, z_1)[/itex], or of finding anything at [itex](x_2, y_2, z_2)[/itex]. You get the probability of simultaneously finding one particle at one location and the other particle at the other location.
zhanhai said:This makes very good sense. But it assumes that the wave functions (WFs) of the two particles cannot be separated. The general validity of this assumption should be by itself related to the subject question. On the other hand, when the two particles' wave functions can be separated, the overall wavefunction of the two, as a product of individual WFs (or a summation of such products), would be more or less artificial, and the proposed understanding of that WF of each particile be seen as the substance distribution of that particle can still make sense.
That assumption is built into the formalism of quantum mechanics. Any time you see two particles being treated as if their wave functions are separate entities, you are looking at an approximation (although if one of the particles is on Earth and the other one is in the Andromeda galaxy, it's a really good approximation). Thus, the idea that ##\psi(x,t)## represents a the density of some material substance stops working as soon as you replace the approximation with the exact solution in which the wavefunction cannot be written in that form.zhanhai said:But it assumes that the wave functions (WFs) of the two particles cannot be separated. The general validity of this assumption should be by itself related to the subject question.
The wavefunction is a mathematical representation of the probabilities of finding a particle in a certain position or state. It does not have a physical presence or substance that can be directly observed.
Experiments such as the double-slit experiment and the photoelectric effect have shown that particles can behave as both waves and particles, depending on how they are observed. This suggests that the wavefunction is not a physical substance, but rather a description of the behavior of particles.
Unlike other physical substances, the wavefunction does not have a definite location or momentum. It is a mathematical concept that describes the probability of finding a particle in a certain state, rather than a physical object with specific properties.
No, the wavefunction cannot be directly observed or measured. It is an abstract mathematical concept that is used to make predictions about the behavior of particles.
Understanding that the wavefunction is not a physical substance is crucial for understanding the behavior of particles at the quantum level. It allows us to make accurate predictions about their behavior and has led to many important discoveries in the field of quantum mechanics.