Coherence, decoherence and the observer of the state wave

The state wave is a probability wave

The state wave in quantum physics is the solution of the Schrödinger equation, it is thus a mathematical object. This mathematical object predicts the probability of an object, to which that state wave relates, to be found at a given time and location when doing a measurement. Because it is a wave, its medium, whatever that is, should be coherent. The coherence of this state wave plays an important role in quantum physics. When a measurement takes place, the state wave ends abruptly and the object is observed. The end of that wave is often called the decoherence of the state wave. An understanding of what is meant by coherence and decoherence is therefore important for a better understanding of quantum physics.

A coherent phenomenon

In order to exhibit wave behavior, a form of cohesion of the medium is required plus a force that strives for the middle position. In water, this cohesion results from the direct physical connection and attraction of the water molecules. It is gravity that returns the medium to the middle position, the rest position of the water surface. Gravity thus ensures the return to the middle position of the wave. The physical connection, the coherence, of the water molecules ensures that the movement is propagated in the medium.

Surface wave in a liquid. The liquid particles perform a circular movement. So there is no liquid transported by the wave in the direction of the wave.

With a sound wave in air, the air pressure is the force that strives for the middle position. This ambient pressure ensures a return to the middle position. In the middle position, the pressure is therefore equal to the ambient pressure. The coherence of the medium transporting sound waves in air stems from the continuous collision of air molecules, through which they constantly exchange their energy. A sound wave is therefore a coherent phenomenon. This means that the air provides coherence, just like with a liquid.

No air molecules are transported in a sound wave, only areas of high and low pressure. Switching on the sound system does not lower the pressure in the room by transporting air molecules out of the room.

With electromagnetic waves, EM waves, such as light, the coherence is ensured by the fact that a changing magnetic field also causes a changing electric field. And vice versa. These changes are therefore closely related and evoke each other. The force that makes the EM wave return to the middle position is a bit more difficult. Electric and magnetic fields tend to extinguish gradually when there is no electrical or magnetic charge nearby. Only their mutual dynamics keep them moving. The force to the middle position is therefore a result of the tendency of an oscillating field to lose its energy. This is again a result of the tendency of an electric or magnetic field to spread in space at the speed of light in all directions, so that the local strength must quickly decrease. That an electric or magnetic field spreads in space in this way is a fundamental but also an unexplained phenomenon. We still don’t even know what it is. We only know very well how it behaves.

EM wave. The electric (E) and the magnetic (B) field forces are perpendicular to each other. The change in electric field strength causes a change in magnetic field strength .. and vice versa. This only functions well if the wave moves at the speed of light.

The quantum state wave and the observer

The quantum physical state wave is somewhat more difficult. As far as we can judge and know, it is a wave of potential, of possible observations, in which the probabilities of position and movement, more exactly the probabilities of showing these properties when measured, alternate. This is thus a wave of potential. Potential is clearly immaterial. The object – before its measurement – is not. Position and movement do conflict with each other. If the position changes then that is clearly movement. As soon as there is movement, the position becomes more variable, so it becomes more uncertain. But as soon as the position is more certain, the movement decreases.

In short, standstill is the absence of movement, movement is the absence of standstill. That is therefore also a form of coherence between these two phenomena, position and movement, in which wanting to know position and/or movement is the driving force. In this wanting to know, we immediately, hopefully, recognize the observer’s influence on his observation, which is just having an experience, and perhaps understand a bit more of the non-material nature of the state wave.

Yin and Yang. Standstill is the absence of movement, movement is the absence of standstill

Loss of coherence?

So, can you still speak of a collapse? Can something that is not material, so is not really there in the sense that we are assigning to the idea of materiality, collapse? We never see such a sudden loss of cohesion in all the waves that we can observe unless we take very special measures. Such as the sudden removal of the medium in which the wave propagates. There is then no longer any sound propagating in that vacuum. In an analogous way would a measurement then suddenly annihilate the medium in which the state wave propagates. The appearance of the measured object from nothing is even more mysterious.

Citing decoherence as a cause of the loss of coherence that is the end of the state wave is a tautological trick. Using the description of the event, the name we give it, as a logical explanation is a tautology. It rains because it rains. The wave disappears because the wave disappears. Decoherence is just a label and very probably a misnomer.

An immaterial wave of potential

Now back to the, in my opinion most likely, cause of the transition from the state wave, that wave of potential, to the observed object. This, the transition from potential into realization, happens in our experience, which is the becoming aware of what is observed. It is here that we see the influence of the observer. This is not to say that the awareness of the act of observing something, inexorable means that the observed objects then materially concrete exist. Just think of what we observe in our dreams.

Why are we convinced that the quantum state wave exists when we cannot observe it? That’s because of all these double-slit experiments, the result of which can only be explained as the result of a wave phenomenon. The overwhelming evidence of it.

I have said already a lot about the influence of the observer on what is observed elsewhere. That is something that Einstein saw very early on already as a consequence of quantum mechanics and he did not like it at all. So, he used the predicted effect, the observation of the slit influencing the outcome of the experiment, which is the dissappearance of the fringes, therefore as an argument for his deep suspicion that quantum mechanics could not be a complete theory. Complete in the sense that its predictions were in all circumstances correct. But he was proved right in a way by various experiments that indeed demonstrated the observer effect he had predicted. Quantum mechanics was therefore right in its predictions. Too bad for Einstein.

I refer those who still have doubts about the reality of the observer effect to this fascinating interview with Professor Donald Hoffman below who makes a very convincing argument for the case of primary consciousness. He aasumes a network of a multitude of conscious agents. For an article by him on this, just google for ‘Objects of Consciousness’ or click here for the pdf.