Comments about "Interpretations of quantum mechanics" in Wikipedia
This document contains comments about the article Interpretations of quantum mechanics in Wikipedia
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Contents
Reflection
Introduction
The article starts with the following sentence.














1 History










2 Nature










3 Interpretive challenges

1. Abstract, mathematical nature of quantum field theories: the mathematical structure of quantum mechanics is abstract without clear interpretation of its quantities.

When any theory is only mathematics, it can never be used to explain something physical. Any explanation or theory clearly requires physical observations, experiments and measurements.

2. Existence of apparently indeterministic and irreversible processes: in classical field theory, a physical property at a given location in the field is readily derived. In most mathematical formulations of quantum mechanics, measurement is given a special role in the theory, as it is the sole process that can cause a nonunitary, irreversible evolution of the state.

This text is not clear.

3. Role of the observer in determining outcomes: the Copenhagentype interpretations imply that the wavefunction is a calculational tool, and represents reality only immediately after a measurement, perhaps performed by an observer; Everettian interpretations grant that all the possibilities can be real, and that the process of measurementtype interactions cause an effective branching process.

Much of what is written is not clear. In order to understand observations are important, because what you want to understand is the behaviour or evolution of the process. But the function of the observer is passive and is not a part of this process.

4. Classically unexpected correlations between remote objects: entangled quantum systems, as illustrated in the EPR paradox, obey statistics that seem to violate principles of local causality.

The explanation that the results of a process or reaction are correlated lie in the details of the reaction and not the process of measuring. The results of the reaction will be the same as if no measurements took place
but are unknown to the outside world.








4 Influential interpretations










4.1 Copenhagen interpretation










4.2 Many worlds










4.3 Quantum information theories










4.4 Relational quantum mechanics










4.5 QBism










4.6 Consistent histories










4.7 Ensemble interpretation










4.8 De Broglie–Bohm theory

The de Broglie–Bohm theory of quantum mechanics (also known as the pilot wave theory) is a theory by Louis de Broglie and extended later by David Bohm to include measurements.

The study of the behaviour of elementary particles (and beyond) should start with experiments i.e. measurements.

Particles, which always have positions, are guided by the wavefunction.

Particles, which always have a position is true.
Their behaviour is not guided by a wavefunction. A wavefunction is a mathematical description of a wave.
Particles are also not guided by waves. Except water waves.

The wavefunction evolves according to the Schrödinger wave equation,

What exactly is the Schrödinger wave equation?

and the wavefunction never collapses.

That is a strong point of the De Broglie–Bohm theory, but requires a certain explanation.



The theory takes place in a single spacetime, is nonlocal, and is deterministic.

This sentence uses three concepts: single spacetime, nonlocal, and deterministic, which are all not clearly defined.

The simultaneous determination of a particle's position and velocity is subject to the usual uncertainty principle constraint.

The uncertainty principle constraint assumes position and momentum. Position and velocity seems better, but velocity requires the measurement of position twice.



The measurement problem is resolved, since the particles have definite positions at all times.

I 100% agree with that, but that does not solve the measurement problems caused as a result of human/physical limitations.






4.9 Quantum Darwinism










4.10 Transactional interpretation










4.11 Objective collapse theories










4.12 Consciousness causes collapse (von Neumann–Wigner interpretation)










4.13 Quantum logic










4.14 Modal interpretations of quantum theory






4.15 Timesymmetric theories
Adapted 2023.



Several theories have been proposed which modify the equations of quantum mechanics to be symmetric with respect to time reversal.

Time reversal is amathematical operation.

This creates retrocausality: events in the future can affect ones in the past, exactly as events in the past can affect ones in the future.

This mathematical possible, but not physical. The evolution of every process evolves in the future. A ball always rolls down hill. Using time reversal in an differential equation that describes this behaviour, the ball moves up hill, but that can't experimental be verified..

In these theories, a single measurement cannot fully determine the state of a system, but given two measurements performed at different times, it is possible to calculate the exact state of the system at all intermediate times.

When a ball rolls down hill from point a,ta to point v,tb the path follows the shape of the hill. Friction has to be included.



The collapse of the wavefunction is therefore not a physical change to the system, just a change in our knowledge of it due to the second measurement.

Any measurement involves in some way or an other a physical change, which creates information, which can de described, and be read and understand by any human being.
To call such a measurent 'collapse of a wave function' is strictly speaking a description of this physical change



Similarly, they explain entanglement as not being a true physical state but just an illusion created by ignoring retrocausality.

This explanation is not clear. Entanglement is a correlation between particles (photons) created as a result of an experiment. There exists no physical connection between the particles created




4.16 Other interpretations










5 Comparisons










6 The silent approach










7. See also
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Created: 11 January 2022
Updated: 8 December 2023
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