Comments about "Bohr-Einstein_debates" in Wikipedia

This document contains comments about the article Bohr-Einstein_debates in Wikipedia
In the last paragraph I explain my own opinion.




The article starts with the following sentence.
The consensus view of professional physicists has been that Bohr proved victorious in his defense of quantum theory, and definitively established the fundamental probabilistic character of quantum measurement.
The issue is that all measurements (classical and quantum) have a probabilistic element.

1. Pre-revolutionary debates

Einstein was the first physicist to say that Planck's discovery of the quantum (h) would require a rewriting of the laws of physics.
This sentence is too strong. The wording "rewriting of the laws of physics." is an overkill.
To support his point, in 1905 he proposed that light sometimes acts as a particle which he called a light quantum (see photon and wave–particle duality).
The issue is that photons can interfer which each other and can be counted.
Bohr was one of the most vocal opponents of the photon idea and did not openly embrace it until 1925

2 The quantum revolution

The shocks for Einstein began in 1925 when Werner Heisenberg introduced matrix equations that removed the Newtonian elements of space and time from any underlying reality.
More text is required to understand this.
The next shock came in 1926 when Max Born proposed that mechanics were to be understood as a probability without any causal explanation.
More text is required to understand this.
The point is that there is a difference between the (underlying) reality and the measurement of this reality.
Einstein rejected this interpretation. In a 1926 letter to Max Born, Einstein wrote: "I, at any rate, am convinced that He [God] does not throw dice."
I agree. Probability issues are measurement issues and are not facts of the physical world, the state of which is unknown.
At the Fifth Solvay Conference held in October 1927 Heisenberg and Born concluded that the revolution was over and nothing further was needed. It was at that last stage that Einstein's skepticism turned to dismay. He believed that much had been accomplished, but the reasons for the mechanics still needed to be understood.
I agree with Einstein.
Einstein's refusal to accept the revolution as complete reflected his desire to see developed a model for the underlying causes from which these apparent random statistical methods resulted.
This is a rather crooked sentence. Maybe the next is better:
"Einstein's refusal to accept the revolution as complete, reflected his desire to see a model for the underlying relations and causes from which these apparent random results evolved."
He did not reject the idea that positions in space-time could never be completely known but did not want to allow the uncertainty principle to necessitate a seemingly random, non-deterministic mechanism by which the laws of physics operated.
His objections are correct.
Einstein himself was a statistical thinker but disagreed that no more needed to be discovered and clarified
In fact Einsteins opinion was that the debate was not over. Correct.
Bohr, meanwhile, was dismayed by none of the elements that troubled Einstein. He made his own peace with the contradictions by proposing a principle of complementarity that emphasized the role of the observer over the observed.
What Bohr should have emphasized is the limitations of what is observed, compared with the underlying reality.

3. Post-revolution: First stage

In the first stage, Einstein refused to accept quantum indeterminism and sought to demonstrate that the principle of indeterminacy could be violated, suggesting ingenious thought experiments which should permit the accurate determination of incompatible variables, such as position and velocity, or to explicitly reveal simultaneously the wave and the particle aspects of the same process.
The problem is that all of this can not be decided by a thought experiment.

3.1 Einstein's argument

Einstein pointed out how it was possible to take advantage of the (universally accepted) laws of conservation of energy and of impulse (momentum) in order to obtain information on the state of a particle in a process of interference which, according to the principle of indeterminacy or that of complementarity, should not be accessible.
Noone objects the law of conservation of energy or impulse. The issue is how to prove (use) them in reality i.e. in an actual experiments. The issue is the accuracy of the measurements, which involve propabilities. See Reflection 1 - Two slit experiment

3.2 Bohr's response

3.3 The principle of indeterminacy applied to time and energy

3.4 Einstein's second criticism

3.5 Bohr's Triumph

4 Post-revolution: Second stage

The second phase of Einstein's "debate" with Bohr and the orthodox interpretation is characterized by an acceptance of the fact that it is, as a practical matter, impossible to simultaneously determine the values of certain incompatible quantities, but the rejection that this implies that these quantities do not actually have precise values.
The issue is that certain parameters in principle can be measured but in combination not.
The position of a particle can be measured (within certain constrains) but its speed not (is much more difficult). In the case of a photon: its position can be 'measured', but not its speed because measuring the position 'destroys' the photon.

5 Post-revolution: Third stage

5.1 The argument of EPR

5.2 Bohr's response

6 Post-revolution: Fourth stage

7. See also

Following is a list with "Comments in Wikipedia" about related subjects

Reflection 1 - Two slit experiment

The problem with the two slits experiments experiment is that it should be performed under different conditions. The idea is that in each experiment setup only one parameter should be changed. My prediction is that at close distance there is no interference pattern. At average distance the interference pattern starts and at large distance you will observe an interference pattern. That is the situation as depicted in Figure A.
The explanation is that at close distance the left half of the pattern is caused by photons which go through the left slit and the right half of photons which go through the right slit.
In case when the background distance is large the pattern is caused (at each point) by two photons of which one goes through the left and one goes through the right slit.
There is no quantum superposition involved. Anyway that therminology should not be used.

Reflection 2

Reflection 3


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Created: 12 December 2017

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