What in the world are you talking about, Johan? Have you changed your mind for that sentence and decided that the QM wavefunction ψ must be real?
How long must I still try and teach you what wave amplitudes are and what the difference between a running wave and a stationary wave is? Really, I would like to know at which Universities you have studied so that I can advise my students to avoid those institutions.
Whether the wave has a real wave amplitude (like a light wave) or a complex amplitude (lke a matter wave) you can write for both at
any point within the wave intensity that the wave amplitude PSI is:
PSI =(modPSI)*exp(itheta(x.t))=(modPSI)*exp[i(S-(omega)t)]
Firstly one should remember that the phase angle ALWAYS changes with time, and only changes with position in a certain manner which dependes on whether the wave is a running wave or a standing wave.
It is also important to note that this expression is true at of EACH and EVERY point within the wave-intensity, not just at a selected point around a circular symmetry axis. It is also valid when there is no polar or spherical symmetry involved at all. This means that at EVERY point in the wave's intensity-field, no matter what shape or symmetry it has, this equation defines an Argand-plane within which (modPSI) is a radius-vector that is rotating around the origin of the Argand plane with an angular frequency (omega): Thus you CANNOT generally equate S with a polar angle around an axis that defines circular symmetry at all.
1. When PSI is a real amplitude (as for a light-wave) we can only observe the projection of the radius-vector (modPSI), at a point within the intensity-field of the wave, as the projection of (modPSI) along the real axis of the Argand plane. This allows one to solve the wave equation by starting of with a complex wave amplitude, as long as you remember that at the end of you calculation you must take the
real part of the complex solution as the actual solution
Now as far as the position-dependent part S of the phase-angle is concerned: For a harmonic wave with a frequency (omega) one has
only that S is continuous and therefore differentiable when you have a
running wave. In this case S
always changes with position
perpendicularly to the moving wave fronts: For example, if the wave-fronts are flat and moving along a direction x, one has that S=kx where k is the wave-vector in reciprocal space. When the wave fronts are circular or spherical one has that S=kr. S only has a gradient perpendicular to the moving wave-fronts which always move in such a manner that they are
parallel to each other: And only by integrating along such a perpendicular
linear direction can you end up with 2n(PI) for the angular dependence. Thus S cannot change with position
along a wave-front at all.
Furthermore, you cannot have wave fronts following each other along a circular path since they will not be parallel, and therefore you cannot write that S=ks, where s is measured perpendicularly to the wave fronts along the circumference. Thus to assume that you can integrate the gradient of S along a circular path and obtain 2n(Pi) is pure physics nonsense and it also violates the foundations of vector calculus.
When it is a stationary wave, the function S does not change between the nodes of this wave but flips discontinuously through PI at every node. Thus in this case you cannot differentiate this function at all.
2. When the wave amplitude is a complex function (like an electron wave) there is still an Argand plane at every point within the intensity of the wave within which (modPSI) forms a radius vector: BUT in this case we observe both projections along the real-axis and the imaginary axis simultaneously. Thus, although in this case you have the same phase angle changing in the same way with position, you, however, find that when you solve the wave equation as if it is a "free" wave which can move linearly through space, the intensity obtained within our three-dimensional space does NOT have crests and troughs which pushes the wave to move along the direction in which it is supposed to move. In fact, the solution that is obtained mandates that there is no change in intensity with position anywhere within our three-dimensional space: So the solution IS NOT that of a running wave; but an infinitely long stationary wave. The fact is that the Schroedinger wave-equation give solutions which can never be running waves at all.
I believe that the correct solution for an electron within its inertial refrence frame is a radially symmetric Gaussian wave around the electron's centre-of-mass. Although the (modPSI) radius vector changes with position, the phase angle at every point is exactly in tune: All the (modPSI) radius vectors move around their origins in phase: Like one-armed clocks with different lengths for their arms.
But we know that a moving electron does act like a running wave with crests and troughs. So where does the de Broglie wavelength then come? It comes from Einstein's special theory of relativity: It obviously MUST be determined by relativity since the momentum and thus de Broglie wavelength for a moving electron has different values within inertial refrence frames that moves relative to each other.
Now consider a stationary Gaussian wave within the electron's inertial refrence frame, and consider an observer doing measurements on this electron within another reference frame moving with a speed v relative to the stationary electron. Now when you Lorentz-transform the stationary Gaussian wave into the observer's moving reference frame, you find that the wave LENGTHENS (correct! there is no length contraction) and that the time along this length is not the same at every point: it varies linearly from past to future within the wave. Thus the radius vectors within the Argand planes at these different points are now not rotating in phase anymore: Crests and troughs develop that allows the electron to be diffracted.
Thus if you solve the Schroedinger wave equation assuming that you can have a macro-running wave with crests and troughs running around a ring, you are assuming a solution which is not possible at all. It is thus utter nonsense to maintain that you can derive the change in positional phase-angle by taking a circular integral within the gradient od S. The gradient of S can ONLY change perpendicularly to wave-fronts which are completely parallel to each other.