Quantum Mechanics again

QM seems to have a practically unfathomable reservoir of surprises. A recent work on Progressive field-state collapse and quantum non-demolition photon counting by Christine Guerlin, Julien Bernu, Samuel Deléglise, Clément Sayrin, Sébastien Gleyzes, Stefan Kuhr, Michel Brune, Jean-Michel Raimond & Serge Haroche, published in Nature 448, 889-893 (23 August 2007) has caught my attention.

The experiment is designed to observe, with as little disturbence as possible, the quantum state of a cavity containing an initially unknown number of photons. The authors describe it as follows:

The irreversible evolution of a microscopic system under measurement is a central feature of quantum theory. From an initial state generally exhibiting quantum uncertainty in the measured observable, the system is projected into a state in which this observable becomes precisely known. Its value is random, with a probability determined by the initial system's state. The evolution induced by measurement (known as 'state collapse') can be progressive, accumulating the effects of elementary state changes. Here we report the observation of such a step-by-step collapse by measuring non-destructively the photon number of a field stored in a cavity. Atoms behaving as microscopic clocks cross the cavity successively. By measuring the light-induced alterations of the clock rate, information is progressively extracted, until the initially uncertain photon number converges to an integer. The suppression of the photon number spread is demonstrated by correlations between repeated measurements. The procedure illustrates all the postulates of quantum measurement (state collapse, statistical results and repeatability) and should facilitate studies of non-classical fields trapped in cavities.

I must admit that my understanding of QM gets more and more inadequate with every such report. For example I do not understand how the `non-destructive' measurements, proposed by the authors really influence the state of the photons. Perhaps they do not change their number.

In this experiment, light is an object of investigation repeatedly interrogated by atoms. Its evolution under continuous non-destructive monitoring is directly accessible to measurement, making real the stochastic trajectories of quantum field Monte Carlo simulations

What is observed is the collapse of the state into one with a defined number of photons. Then the observed number remains constant - until the cavity absorbs one of the photons (on a much larger timescale) and then the measurements show this smaller number.

When I find the words `repeated interrogation' my mind jumps to `continuous measurement' and thus to the Quantum Zeno Effect. Is there any connection?

And one more remark: the short article on the discovery on physicsworld.com has attracted a few comments. By far the most extensive is one by Andrei P. Kirilyuk, who is a champion of "Universal Concept of Complexity by the Dynamic Redundance Paradigm: Causal Randomness, Complete Wave Mechanics, and the Ultimate Unification of Knowledge"

OK, OK - I admit I do not iunderstand him neither. But there are some tell-tale signs of going beyond normal science. Such as mentioning by Kirilyuk that ALL famous science creators, from Descartes and Newton to Einstein and de Broglie were notorious mavericks understood by almost nobody at the time of their discoveries. Which supposedly builds up his credentials. This reminds me of a famous quote:
They laughed at Copernicus.
They laughed at the Wright Brothers.
Yes, well, they also laughed at the Marx Brothers.
Being laughed at does not mean you are right.
Another signal is that Citebase lists 18 articles quoting the Kirilyuk work ... all of them by ... Kirilyuk himself.


Concluding: it is difficult to follow the new developments in physics. A lot depends on the peer review. But - should we have some sort of mechanism for the strange approaches that are out of the mainstream science? Would the famous EPR paper be published today? Especially if the author list did not include Einstein?

Quantum Mechanics again: point for experimentalists

Understanding the basic principles of QM is really difficult. The philosophical and theoretical discussions, even those coupled with a lot of more or less developed mathematics are only adding to the confusion. Of course - they are needed - because thanks to such theoretical musings as EPR's or Bell's the path may be opened for experimental evidence. And such evidence, very often, is more surprising than we could expect.

A fine example is provided by
Jacques, V.; Wu, E.; Grosshans, F.; Treussart, F.; Grangier, P.; Aspect, A. & Roch, J. Experimental realization of Wheeler's delayed-choice gedanken experiment. Science, 2007, 315, 966-968

Let me just quote here the conclusions of the paper:

Our realization of Wheeler’s delayed choice Gedanken Experiment demonstrates beyond any doubt that the behavior of the photon in the interferometer depends on the choice of the observable which is measured, even when that choice is made at a position and a time such that it is separated from the entrance of the photon in the interferometer by a space-like interval. In Wheeler’s words, since no signal traveling at a velocity less than that of light can connect these two events, “we have a strange inversion of the normal order of time. We, now, by moving the mirror in or out have an unavoidable effect on what we have a right to say about the already past history of that photon”. Once more, we find that Nature behaves in agreement with the predictions of Quantum Mechanics even in surprising situations where a tension with Relativity seems to. appear

I wonder if this result will hold on repetitions. If yes, then this would reaffirm that we have a lot to understand yet. Especially about time in Quantum Mechanics.

Bell theorem refuted!!! Or just another pseudo-physicist.

Recently I have found a very curious piece of information on Bell Theorem.
And this was even stranger. The news came from Causation: International Journal Of Science.
It claims to be peer reviewed scientific electronic journal.

The front page boasts exploding graphics with a title Bell's
theorem …refuted! in one inch letters .

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Figure 1: That's what I call a scientific journal! Not some dull, blank blue page as Phys Rev Letters...

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Inside one finds two (!) peer reviewed papers by Ilija Barukčić:
Bell's theorem. A fallacy of the excluded
middle and Helicobacter pylori: the cause of human gastric cancer. Perhaps not surprisingly, the Editorial Board consists of — you guessed: Ilija Barukčić!

But I was curious to see, if indeed, this recent work has resulted in a refutation of Bell theorem (making a lot of my own effort to prove it for myself - succesfully - useless and wrong).

I dug into the first article (which was quite cumbersome — as the text is really overfull of mathematical formulae, repeated endlessly). The conclusions of the author are really bold:

As proofed above, Bell's theorem is fallacious because of specifically logical reasons. The logic of Bell's theorem is not sound. Bell's theorem contradicts classical logic, it is based upon a fallacy. In so far either
Bell's theorem is valid or classical logic is valid but not both. Bell's theorem is not compatible with the law of the excluded middle, it is a fallacy of the excluded middle. Bell has committed the fallacy of the excluded middle, commonly referred to as a false dilemma. This logical fallacy is sometimes known also as a false correlative, an either/or fallacy, a bifurcation or as black and white thinking. Bell's formalisation of local realism, his starting point, is incorrect and is based on a logical contradiction. Bell's theorem, as a false dilemma fallacy, refers to a misuse of the law of the excluded middle. Bell has misapplied the law of excluded middle at an maximum. An extreme simplification, a wishful thinking and a misapplication of the law of the excluded middle is the foundation of Bell's theorem. In so far,
Bell's theorem is the most profound logical fallacy of science.

Further, Bell's theorem is the definite and best proof known, that correlation analysis contradicts Quantum mechanics and Relativity Theory, that it is a useless and dangerous statistical machinery. Thus, as proofed above, Bell's theorem is refuted definitely, the book on Bell's theorem is completely losed.

Finally I got to the essence of the proof of refutation of Bells theorem. It may be found first on page 18 of the paper. I'll try to repeat here the most important step, taking the liberty of radically simplifying the notation. I ask the Reader to excuse the use of formulae here, but I think it is such a mathematical joke, that should be shared.

The Bell's theorem is given by Barukčić as:

( 1 − ( (1 − (At ) )· ( 1 − (Not At )) ) ) ≥( Not At) + ( Not Ct ) · ( ( At ) − (Bt ) ). (1)

Let's simplify it by denoting the left and right side of equation:

( 1 − ( (1 − (At ) )· ( 1 − (Not At )) ) ) = L (2)

( Not At) + ( Not Ct ) · ( ( At ) − (Bt ) ) = R (3)

This really helps, as there are really no operations on L and R in the `proofs'. Thus what we have is the inequality

L≥ R (4)

What Barukčić aims at is a proof by reductio ad absurdum, i.e., he assumes the theorem to be true, and looks for logical discrepancies. There are four `proofs' and I'll present the first of them, quoting the author as much as it is possible (some substitutions and cuts are put in here, the Reader interested in details can check the original paper).

The term R can take the values 0 or 1. In so far, let us assume, that R = 0. We
obtain equation L ≥ (R=0).

It is generally accepted, that a ≥ b means that a = b or a > b, both are equally allowed and
possible, if the inequality is true. In so far, Eq. 1 is true, if L=0.
Eq. 1 is equally true if L > 0. In this case, let us assume¹, that
L = (R=0),
which satisfies Bell's inequality. On the other hand, Bell is respecting classical logic and thus the law of the excluded middle. The law of excluded middle in classical bivalent logic must yield L=1. Bell's inequality is respecting this law. We obtain

(L=1) = (R=0) (5)

Bell's inequality leads to a logical contradiction, it not true that 1 = 0. Therefore, our original assumption, that Bell's theorem is correct is false.

This was the first of the four `proofs'. Of course, if one assumes to use equality and to use R=0 condition then one gets contradiction. But it is not the Bell theorem that `contradicts classical logic and leads to a logical contradiction' — it is the author himself.

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1

Emphasis mine. There is no emphasis on this assumption in the original paper...

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This document was translated from L^AT_EX by
H^EV^EA.

Quantum question

A recent preprint on Time in Quantum Theory by Dieter H Zeh has brought my attention
to the question of the `speed of quantum changes'. While the classical discussions of nonlocality
in Quantum Mechanics (QM) and consequences of Bell's Theorem are widely published, 
there are some other situations where nonlocality is rather hard to grok.

Consider a hydrogen atom in excited state. The electron wavefunction has some specific form, extending via exponentially vanishing factor, to infinity.
Now, when the atom emits a photon (preferably for this analysis in spontaneous emission)
the wavefunction changes. 
Question: does the wavefunction change at the same moment in the whole space?
Or, as Zeh suggests, is there a `wave' of changing wavefunction, spreading our from the atom?

Anyone knows any solution / references to this problem?