Comments about: Packet man - Quantum Physics

Comments about the article in Nature: Packet man - Quantum Physics

Graham Farmelo delights in a study of Albert Einstein's under-appreciated contributions to quantum theory.
I think there are two issues at stake: Einstein's huge contributions to the quantum theory and his doubts.: In 1941 US physicist John Wheeler visited Albert Einstein etc. The sage of Princeton listened in silence as Wheeler set out his case, but afterwards was no more enthusiastic.
I think that Einstein was clever and kept a low profile. I think that Einstein agreed with certain aspects but not with all. May be you have to read to book to get better informed.: Many of his colleagues thought his (Einstein's) views on quantum theory cranky - Robert Oppenheimer dismissed them as "cuckoo"
The problem with the word "quantum theory" is that it covers (describes) a brought area of research. You should always specify in more detail which area you want to discuss.: In the book "Einstein and the Quantum" Douglas Stone attempts to put that right.
It would have be nicer if here was written: In the book "Einstein and the Quantum" Douglas Stone puts that right in the following areas .... but not in ....: Stone covers all this with clarity and even tackles Einstein's little known 1917 paper on the quantization of chaotic systems.
See also the article: Einstein’s Unknown Insight and the Problem of Quantizing Chaos by A. Douglas Stone.

In the article by A. Douglas Stone we read (at page 2):
As long as the force law is not exactly proportional to 1/r2 or r, the mass’s orbit will typically not close on itself: In astronomical terminology, it will precess;

The same is true when the force is proportional to 1/r2 but does not point to the center of mass of the first object using Newton's Law.

Einstein would have been aware of that fact from his work on the relativistic theory of the precession of the orbit of Mercury!

Exactly also true using Newton's Law.

Equation 4 says that quantization is achieved by setting 2 * pi * L = n * h.
In other words, L = n * h', the familiar Bohr rule for the quantization of angular momentum for an arbitrary central force law. The second loop integral will quantize the energy of the motion and its precise form will depend on the particular force law.

The simplest case is that n=1. What does this physical mean? Is this the energy of a photon? of a certain frequency?
At page 3 we read:

physicists now understand that inte-grable systems are highly exceptional and that the generic case — the nonintegrable system — always has some regions of phase space where the dynamics are chaotic, that is, where trajectories are exponentially sensitive to initial conditions.

Generally speaking all processes are sensitive to initial conditions. It is an exception when this is not the case.
But there is more. All processes are also sensitive to additional process parameters, which are often unknown.
One example is for example friction. If you place a ball inside a torus and you give a ball a reasonable speed the outcome is completely unpredictable at which position it will come to rest. The reason is friction.
In the paragraph A modern perspective we read:

To clarify the relationship between Einstein’s type (a) and type (b) motion and what is now called regular and chaotic motion, one can turn to dynamical billiards, which are paradigms for the study of classical and quantum chaos.

You can ask you self the question what this has to do with the quantum theory.

Figure 3. Billiards. (a) Generic trajectories in a circular billiard are quasiperiodic.

The problem with all 4 examples is that they are artificial because no friction is included. When friction is included they all become indeterministic.

Figure 5. Chaotic wavefunction of the stadium shaped billiard.

This is a typical artificial problem. The reality does not show this behaviour.
The article ends with the following sentence:

Although Einstein’s antipathy to certain aspects of modern quantum theory is well known, there appears to be a renewed appreciation this year of his seminal contributions to quantum physics.

Unfortunate in this document those aspects are not mentioned nor is there an indication if Einstein was right.

With his introduction of the photon concept in 1905, his clear identification of wave–particle duality in 1909, his founding of the quantum theory of radiation in 1916, and his treatment of the Bose gas and its condensation in 1925

This list identifies Einstein's huge contributions to the Quantum Theory and the fact that he did not agree with other issues, with which he was propably right, made him a giant in physics.

Reflection

One of the most important questions to answer is: How important is this document? How important is this concept of quantification?
Niels Bohr introduced in 1913 what is called The Bohr Model (Wiki) . Together with the Rydberg formula gives this a good description what is happening at atomic level.
The period before 1925 is called the Old quantum theory (Wiki). The article by Douglas Stone falls (partly) in that cathegory.
After 1925, influenced by Erwin Schrödinger (Wiki) (Schrödinger equation) the quantum theory Quantum mechanics (Wiki) was develloped.
In the document: Schrödinger equation - Historical background and development (Wiki) You can read:
Schrödinger, though, always opposed a statistical or probabilistic approach, with its associated discontinuities - much like Einstein, who believed that quantum mechanics was a statistical approximation to an underlying deterministic theory — and never reconciled with the Copenhagen interpretation.

The problem is experiments and observations versus mathematics.
When you study the Rydberg formula, the Lyman Series, the Balmer Series etc you can see that observation and mathematics coincide.
For the Schrödinger equation (which involves complex numbers) this is much more difficult. It seems that the theory only can be tested for very simple examples.
A second problem is the sentence: "quantum mechanics was a statistical approximation to an underlying deterministic theory "
IMO this is not correct. IMO:
"quantum mechanics is a statistical approximation to an underlying indeterministic world and only for simple situations"

The same problem exist also with QBits and superposition. You can write a thick book with mathematics using QBits and quantum logic gates, but if there exists no good way to test the input and output of the experiments using QBits than what is the importance of all of this?

The book review continues with the following text:: It was left to Werner Heisenberg, Erwin Schrödinger and Paul Dirac to set out the full-blown quantum theory of matter in the mid- 1920s. Einstein was formidable critic of the theory, although he was always outwitted in argument by his friend Niels Bohr - a topic treated only briefly in the book, probably because this ground is so well-trodden.
Or maybe not? The reviewer shows here some doubts. Again the major problem is that the Quantum Theory covers a broad area. May be the reason is that in certain areas the doubts raised by Einstein was correct and that in those specific areas the Quantum Theory requires modifications. One problem in Quantum Theory is the concept of Superposition. See reflection.: Einstein died less than two years later. He was proud to have built the edifice of relativity, but still profoundly dissatisfied with quantum theory, which he was confident would be superseded
Now I expect a certain evaluation. After all those years still the answer remains: was Albert Einstein correct? In this review there is no answer.: Was he wrong? Some theoretical physicists are now speculating that space and time in some sense emerge from the more fundamental quantum so it may be that scientists will one day regard Einstein's greatest achievement as pioneering a theory he believed was terribly flawed.
In the book "In search of Schrödinger's cat" by John Gribbin space and time are discussed extensive in relation to the Feynman diagrams in the pages 184 to 202. Only briefly the concept space/time is mentioned related to general relativity. I expect that A. Einstein in general would agree with the concept of the Feynman diagrams. Implying that modifying the concept of space and time would not solve an issue but widens the cap.

Reflection part 1 - Superposition

One of the major problems in the Quantum Theory is the concept of superposition which means that (my interpretation) that something can be simultaneous in two states. In the case of "Schrödinger's Cat" the cat can be both alive a death at the same time or simultaneous. This is called: the cat is in a superposition state
The question is: what does this mean. More specific: What does this physical means.
I should also have to add the sentence: "Before I look at it (inside the box)"
The issue is: what have I (or any human) to do with the state of the cat. Or more specific: What have I to do with the physical state of the cat. IMO nothing.
If at some moment during the experiment the cat dies than at that moment the state of the cat changes from alive to dead and stays as such. My observations alone have nothing to do with this.

When you consider an oscillator the value changes continuously between 0, 1, 0, -1 and 0. There is no superposition involved.
You can change an oscillator such that it becomes a Flip Flop. But also here there is no superposition involved because a Flip Flop is either 0 or 1.

In the Usenet thread Quantum mystery explained I try to understand the concept of superposition by raising simple questions based on simple experiments.
The problem is that almost no one answers my questions and if there is an answer than the answer is not clear.
In my opinion the examples do not contain superposition. If the reader agrees than I ask him to modify the experiment such that it involves superposition. Alas, no answer.

My conclusion is that superposition is a rather tricky, vague concept about which we do not want to speak or give our opinion

My overall conclusion is that superposition is not a usefull physical concept. This has serious consequences for quantum computers which require Qbits, because Qbits involve superposition and that concept is a mystery.

Related to superposition, if Einstein had doubts, than he was correct.

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Created: 27 November 2013

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