User:Michael C Price/draft
Draft page. For draft work and formula library.
- 1 Eras
- 2 Afshar/Azeri
- 3 Essays
- 4 Muse
- 5 GR
- 6 ref format
- 7 Result assumption
- 8 Bohm
- 9 Orange Marlin
- 10 Good and bad ghosts - is there a difference?
- 11 Dispute resolution
- 12 Complementarity critique
- 13 Boxes
- 14 History and Development
- 15 Templates
- 16 Dirac equation
- 17 Landau-Lifshitz pseudotensor
- 18 Aether critiques
- 19 Michelson–Morley
- 20 Matrices
- 21 Electroweak Lagrangian
- 22 MWI measurement
- 23 An illustrative example
- 24 Useful References
- 25 Fetus
- 26 References
The following four timelines show the geologic time scale. The first shows the entire time from the formation of the Earth to the present, but this compresses the most recent eon. Therefore, the second scale shows the most recent eon with an expanded scale. The second scale compresses the most recent era, so the most recent era is expanded in the third scale. The third scale compresses the most recent period, so the most recent period is expanded in the fourth scale.
|Preceded by Proterozoic Eon||Phanerozoic Eon|
|Paleozoic Era||Mesozoic Era||Cenozoic Era|
Semi-protect. High level of disruptive IP POV tag teaming over many months. Last 24 hrs has seen 3 IPs at work. Repeated attempts at dialog with IP on talk page fail. --Michael C. Price talk 10:20, 10 November 2009 (UTC)
|Problems playing this file? See media help.|
- Everett FAQ "Could we ever communicate with the other worlds? Why do I only ever experience one world? Why am I not aware of the world (and myself) splitting?"
Peter J. Lewis (2007). “How Bohm’s Theory Solves the Measurement Problem”, Philosophy of Science 74 (5): 749–760 Lewis on Wallace & Brown's identification of Bohm's result assumption Also Lewis “Empty Waves in Bohmian Quantum Mechanics”, British Journal for the Philosophy of Science 58: 787–803 (2007).
Q: Hugh Everett says that Bohm's particles are not observable entities, but surely they are - what hits the detectors and causes flashes?
Occam's razor criticism
Both Hugh Everett III and Bohm treated the wavefunction as a complex-valued but real field. Everett's many-worlds interpretation is an attempt to demonstrate that the wavefunction alone is sufficient to account for all our observations. When we see the particle detectors flash or hear the click of a Geiger counter or whatever then Everett's theory interprets this as our wavefunction responding to changes in the detector's wavefunction, which is responding in turn to the passage of another wavefunction (which we think of as a "particle", but is actually just another wave-packet). But no particle, in the Bohm sense of having a defined position and velocity, is involved in measurement. For this reason Everett sometimes referred to his approach as the "pure wave theory". Talking of Bohm's 1952 approach, Everett says:
|“||Our main criticism of this view is on the grounds of simplicity - if one desires to hold the view that is a real field then the associated particle is superfluous since, as we have endeavored to illustrate, the pure wave theory is itself satisfactory.||”|
In the Everettian view, then, the Bohm particles are unobservable entities, similar to, and equally as unnecessary as, for example, the luminiferous ether was found to be unnecessary in special relativity. In Everett's view, we can remove the particles from Bohm's theory and still account for all our observations. The unobservability of the "hidden particles" stems from an asymmetry in the causal structure of the theory; the particles are influenced by a "force" exerted by the wavefunction and by each other, but the particles do not influence the time development of the wavefunction (i.e. there is no analogue of Newton's third law -- the particles do not react back onto the wavefunction) Thus, if we regard the wavefunction as real and the source of all experience, the particles do not make their presence known in any way; as the theory says, they are hidden, but in a far more profound way than de Broglie and Bohm had intended.
In the Everettian view the role of the Bohm particle is to tag, or select, just one branch of the universal wavefunction; the other branches are designated "empty" and implicitly assumed by Bohm, in what is called the "result assumption", to be devoid of conscious observers. H. Dieter Zeh comments on these "empty" branches:
|“||It is usually overlooked that Bohm’s theory contains the same “many worlds” of dynamically separate branches as the Everett interpretation (now regarded as “empty” wave components), since it is based on precisely the same . . . global wave function . . .||”|
|“||pilot-wave theories are parallel-universe theories in a state of chronic denial.||”|
This conclusion has been challenged by pilot wave advocates, with a number of suggested resolutions; either make the "result assumption" explicit, deny that the wavefunction is as objectively real as the particles or dispute whether the Everett prescription is complete (e.g. can probabilities be derived from the wavefunction?)
Wallace and Brown
(abstract, page 1)
- de Broglie-Bohm theory does have the resources to provide a coherent solution of the measurement problem, but they do not involve the hypothetical corpuscles whose existence is precisely what distinguishes the theory from the Everettian picture of quantum reality.
(page 5)W&B's result assumption, from Bohm part II:
- It is useful to consider of the precise wording of this [result] assumption.
- Now, the packet entered by the apparatus [hidden] variable . . . determines the actual result of the measurement, which the observer will obtain when he looks at the apparatus.
(page 6) W&B's question:
- The crucial question we wish to raise is this. Does this wavepacket, in and of itself, account for the result of the measurement, or does a definite measurement outcome require, even in this case of complete predictability, the presence of the hidden variables within it?
- The Result Assumption appears to be inconsistent with .. or at least to override it in some mysterious way.
- Quantum mechanics, in our view, has both substance and form before the introduction of hidden corpuscles. In fact, we believe the case has already been made elsewhere, the rest of this paper being an attempt to summarise the bones of the argument and to add a bit more new flesh to it.
- the corpuscle’s role is minimal indeed: it is in danger of being relegated to the role of a mere epiphenomenal ‘pointer’, irrelevantly picking out one of the many branches defined by decoherence, while the real story — dynamically and ontologically — is being told by the unfolding evolution of those branches. The “empty wave packets” in the configuration space which the corpuscles do not point at are none the worse for its absence: they still contain cells, dust motes, cats, people, wars and the like. The point has been stated clearly by Zeh:
- It is usually overlooked that Bohm’s theory contains the same “many worlds” of dynamically separate branches as the Everett interpretation (now regarded as “empty” wave components), since it is based on precisely the same . . . global wave function . . .
- Deutsch has expressed the point more acerbically:
- [P]ilot-wave theories are parallel-universe theories in a state of chronic denial.
- It is interesting that at times Bohmians slide into a mode of talking about systems as if they were just made out of corpuscles40, but this is only coherent if the radical position is adopted that the wavefunction is simply not real at all, that it is a piece of mathematical machinery in the quantum mechanical algorithm for the motion of corpuscles. Yet ‘reality’ is not some property which we can grant or withhold in an arbitrary way from the components of our mathematical formalism.
(page 13) Footnote 41:
- Those who sympathise with Leibniz’ claim—fully endorsed by Einstein—that the essence of a real thing is its ability to act and be acted upon, may be interested in a defence of the reality of the wavefunction based on the action-reaction principle found in Anandan and Brown
(page 14/15) On Maudlin:
- Why shouldn’t consciousness supervene as much on wavefunctions as on corpuscles?—a possibility that was clearly entertained by Bohm in 1951. But if one allows for this possibility, the floodgates into the Everettian multiplicity of autonomous, definite perceived outcomes are opened. To restrict supervenience of consciousness to de Broglie-Bohm corpuscles in the brain does succeed in restricting conscious goings-on to one and only one branch of the Everett multiverse but it seems unwarranted and bizarre. The strategy seems unmotivated except by a desire purely to reduce the number of conscious observers in the universe, and it is at best unclear whether this is a reasonable application of Occam’s Razor.
(page 15) Footnote 46:
- As we saw in section 3, even in his hidden variables paper II of 1952, Bohm seems to associate the wavepacket chosen by the corpuscles as the representing outcome of the measurement—the role of the corpuscles merely being to point to it. But if this wavepacket can support consciousness, it is mysterious why empty ones cannot.
(page 15) Footnote 47:
- It is noteworthy that the active role of the corpuscles in the de Broglie-Bohm theory is merely to act on each other, not back on the wavefunction. So it is striking that such passive entities are purportedly capable of grounding consciousness experience. C.f. Stone  and independently Brown .
(page 17) Parting words:
- observation—in so far as this is related to the cognitive process of “knowing” the outcome of the measurement process—is not discovering the position of the de Broglie-Bohm corpuscle even if it exists.
- Harvey R Brown and David Wallace, Solving the measurement problem: de Broglie-Bohm loses out to Everett, Foundations of Physics 35 (2005), pp. 517-540.  Abstract: "The quantum theory of de Broglie and Bohm solves the measurement problem, but the hypothetical corpuscles play no role in the argument. The solution finds a more natural home in the Everett interpretation."
- See section VI of Everett's thesis: The Theory of the Universal Wave Function, pp 3-140 of Bryce Seligman DeWitt, R. Neill Graham, eds, The Many-Worlds Interpretation of Quantum Mechanics, Princeton Series in Physics, Princeton University Press (1973), ISBN 0-691-08131-X
- Daniel Dennett (2000). With a little help from my friends. In D. Ross, A. Brook, and D. Thompson (Eds.), Dennett’s Philosophy: a comprehensive assessment. MIT Press/Bradford, ISBN 026268117X.
- David Deutsch, Comment on Lockwood. British Journal for the Philosophy of Science 47, 222228, 1996
- Craig Callender, "The Redundancy Argument Against Bohmian Mechanics". 
Good and bad ghosts - is there a difference?
The article says:
- The Faddeev-Popov ghosts are sometimes referred to as "good ghosts". The "bad ghosts" represent another, more general meaning of the word "ghost" in theoretical physics: states of negative norm - or fields with the wrong sign of the kinetic term - whose existence allows the probabilities to be negative.
But don't all ghosts imply negative norm states? I notice, reading Cheng and Li, that Faddeev-Popov ghost propagators always have the opposite sign from the analogous non-ghost propagators, which implies the opposite sign for their norm.--Michael C. Price talk 12:48, 2 July 2007 (UTC)
Wikipedia:Resolving disputes Wikipedia:Requests for arbitration Wikipedia:Ignore all rules Wikipedia:Policies and guidelines Wikipedia:How to create policy Wikipedia:Stable versions Wikipedia:Criteria for speedy deletion Wikipedia:Administrators' noticeboard/3RR
- Niels Bohr stated "a complementary way of description is offered precisely by the quantum-mechanical formalism" (1949)
- In this view, since the photons in the experiment obey the precise mathematical laws of quantum mechanics (the formalism), they can be described by Bohr's principle of complementarity. Cf:
- "I think Bohr would have had no problem whatsoever with this experiment within his interpretation. Nor would any other interpretation of quantum mechanics. It is simply another manifestation of the admittedly strange, but utterly comprehensible (it can be calculated with exquisite precision), nature of quantum mechanics."
- "There is absolutely nothing mysterious about Afshar's experiment. [....] And of course, the conventional quantum mechanics is compatible with the principle of complementarity."
- "It was claimed that this experiment could be interpreted as a demonstration of a violation of the principle of complementarity in quantum mechanics. Instead, it is shown here that it can be understood in terms of classical wave optics and the standard interpretation of quantum mechanics."
- Shahriar S. Afshar, "Sharp complementary wave and particle behaviours in the same welcher weg experiment", (2003) IRIMS www.irims.org/quant-ph/030503/; Proc. SPIE 5866 (2005) 229-244; AIP Cof. Proc. 810, (2006) 294-299. (Crossed beam experiment).
- John G. Cramer, "A Farewell to Copenhagen?" (2005), Analog Science Fiction and Fact. (A non-technical discussion in a popular forum)
- Marcus Chown, "Afshar's Quantum Bombshell", "Quantum rebel" (July 24, 2004) New Scientist magazine; "A great leap forward",  (October 6, 2004) The Independent.
- Ira Flatow, "Einstein, Bohr and the Nature of Light", , (July 30, 2004) Science Friday radio prgram, NPR.
- Unruh W (2004). "Shahriar Afshar - Quantum Rebel?". 30. 20: 10. External link in
- Motl L (2004). "Violation of complementarity?". External link in
- Steuernagel O (2005). "Afshar's experiment does not show a violation of complementarity". ArXiv:quant-ph/0512123. External link in
History and Development
The term "orthomolecular" was first used by Linus Pauling in 1968, to express the "idea of the right molecules in the right amounts" and subsequently defined "orthomolecular medicine" as "the treatment of disease by the provision of the optimum molecular environment, especially the optimum concentrations of substances normally present in the human body." or as "the preservation of good health and the treatment of disease by varying the concentrations in the human body of substances that are normally present in the body and are required for health." 
Since 1968 the orthomolecular field has developed further through the works of mainstream and non-mainstream researchers. Despite thus it still is often closely associated by the public with Pauling's advocacy of multi-gram doses of vitamin C for optimal health.
An example of a recent mainstream researcher is nutrition researcher Bruce Ames although he does not use the term itself. However his research deals with nutrition and specific genetic disease conditions (as indeed did Pauling's original article which defined the term "orthomolecular"). Ames' research includes investigating the effects of large doses of, for example, the nutrients alpha-lipoic acid (a coenzyme precursor) and the carnitine (an amino acid complex) on restoring metabolic health, and in particular mitochondrial function, in animal models   Ames has also investigated the role of high dose B-vitamin therapy in alleviating in approximately 50 defective co-enzyme binding affinities, of which one, at least, every human suffers from  (example of one genetic disease condition: Over 40% of the population is hetro- or homo-zygous with the thermolabile variant of 5,10-methylenetetrahydrofolate reductase  and as a result requires extra riboflavin  ).
Ames has, based on his research, developed a supplement for human use.
Definition and properties of the Landau-Lifshitz pseudotensor
The Landau-Lifshitz pseudotensor of the gravitational field has the following construction
is the Einstein tensor
is the metric tensor
G is Newton's gravitational constant.
The Landau-Lifshitz pseudotensor is constructed so that when added to the stress-energy tensor of matter, , its total divergence vanishes:
This follows from the cancellation of the Einstein tensor, , with the stress-energy tensor, by the Einstein field equations; the remaining term vanishes algebraically due the commutativity of partial derivatives applied across antisymmetric indices.
Mainstream critics point out that Einstein's special theory of relativity is an extension of the principles of Galilean relativity or invariance from classical mechanics to include Maxwell's equations and thereby optics.
In the mainstream view, therefore, any attempt to formulate a new aether theory by recourse to Galilean relativity, is doomed since Galilean invariance is already incorporated into special relativity under the name Lorentz invariance; any putative aether is considered to be devoid of mechanical properties, unobservable and hence superfluous. It is held that any non-superfluous aether theory would yield predictions that are incompatible with Lorentz invariance and thereby Maxwell's equations; however the latter is empirically very well attested.
This reference by Einstein in his 1905 paper is probably not about MMX, but to other attempts to detect the ether. Einstein is on record, early on, as saying that he hadn't heard of the MMX null result until after 1905, although later in his life, when we can presume his memory would not be so clear about distant events, he contradicted himself on this point. (Cf A P French's standard textbook (or see Michael Polanyi on this point) - French concludes that Einstein had not heard about the MMX -- and although you can find many texts that assume the reverse, they are wrong, IMO.)
- Michael Polanyi, Personal Knowledge: Towards a Post-Critical Philosophy, ISBN: 0226672883, footnote page 10-11: Einstein reports, via Dr N Balzas in response to Polanyi's query, that "The Michelson-Morely experiment had no role in the foundation of the theory." and "..the theory of relativity was not founded to explain its outcome at all."
A P French, Special Relativity,
The g term describes the gauge fields
The f term describes the interaction between the electrons, muons, and quarks (the Dirac particles) of the Standard Model. The subscripts Li and Ri in and refer to the Left and Right-handed spin of the i-th species of Dirac particles in the Standard Model. This is reflected in the asymmetric form of this term.
The H term describes the Higgs field .
This gives rise to an effective lagrangian with a mass term, where the is mass generated by the interaction of the Higgs with the other varieties of particles given in the Lagrangian:
Measurement and observation are easily handled in MWI. Measurements, or measurement-like interactions, are any interactions that correlate the observer's wavefunction with the observed system's wavefunction. A measurement, when the observed system is a definite state labelled by i, simply induces:
where O[i] represents the observer having detected the object system in the i-th state. In words this simply represents the observer measuring the observed system in the i-th state.
A measurement is complete when:
Before the measurement has started the observer states are identical; after the measurement is complete the observer states are orthonormal. Thus a measurement defines the branching process: the branching is as well- or ill- defined as the measurement is. Thus branching is complete when the measurement is complete. Since the role of the observer and measurement per se plays no special role in MWI (measurements are handled as all other interactions are) there is no need for a precise definition of what an observer or a measurement is – just as in Newtonian physics no precise definition of either an observer or a measurement was required or expected. In all circumstances the universal wavefunction is still available to give a complete description of reality.
An illustrative example
MWI describes measurements as a formation of an entangled state which is a perfectly linear process (in terms of quantum superpositions) without any collapse of the wave function. For illustration, consider a Stern-Gerlach experiment and an electron or a silver atom passing this apparatus with a spin polarization in the left-right or x direction and thus a superposition of a spin up and a spin down state in up-down or z-direction. As a measuring apparatus, take a bubble or tracking chamber (a nonabsorbing particle detector). And finally let a cat observe the bubble tracks that form in the bubble chamber. The electron passes the apparatus and reach the same site in the end on either way so that, except for the up-down z-spin polarization, the state of the electron is finally the same regardless of the path taken (see The Feynman Lectures on Physics for a detailed discussion of such a setup). Before the measurement, the state of the electron and measuring apparatus is:
The state is factorizable into a tensor factor for the electron and another factor for the measurement apparatus. After the spin measurement (bubble formation), the state is:
The state is no longer factorizable -- regardless of the vector basis chosen the state has to be expressed as the sum of a number of terms (in this example, at least two). The state of the above experiment is decomposed into a sum of two correlated or so-called entangled states ("worlds") both of which will have their individivual history without any further interaction or quantum interference between the two due to the physical linearity of quantum mechanics (the superposition principle): All processes in nature are linear and correspond to linear operators acting on each superposition component individually without any notice of the other components being present.
This would also be true for two non-entangled superposed states, but the latter can be detected by interference which is not possible for different entangled states (without reversing the entanglement first): Different entangled states cannot interfere; interactions with other systems will only result in a further entanglement of them as well. In the example above, the state of a Schrödinger cat watching the scene will be factorizable in the beginning (before watching)
but not in the end (after watching)
This example also shows that it's not the whole world that is split up into "many worlds", but only the part of the world that is entangled with the considered quantum event. This splitting tends to extend by interactions and can be visualised by a zipper or a DNA molecule which are in a similar way not completely opened instantaneously but opens gradually, element by element.
Imaginative readers will even see the zipper structure and the extending splitting in the formula:
If a system state is entangled with many other degrees of freedom (such as those in amplifiers, photographs, heat, sound, computer memory circuits, neurons, paper documents) in an experiment, this amounts to a thermodynamically irreversible process which is constituted of many small individually reversible processes at the atomic or subatomic level as is generally the case for thermodynamic irreversibility in classical or quantum statistical mechanics. Thus there is -- for thermodynamic reasons -- no way for an observer to completely reverse the entanglement and thus observe the other worlds by doing interference experiments on them. On the other hand, for small systems with few degrees of freedom this is feasible, as long as the investigated aspect of the system remains unentangled with the rest of the world.
The MWI thus solves the measurement problem of quantum mechanics by reducing measurements to cascades of entanglements.
The formation of an entangled state is a linear operation in terms of quantum superpositions. Consider for example the vector basis
and the non-entangled initial state
The linear (and unitary and thus reversible) operation (in terms of quantum superpositions) corresponding to the matrix
(in the above vector basis) will result in the entangled state
- New/Old Findings on Unique Vitamin E
- AscorbateWeb: Timeline from 1935 to 1939
- Orthomolecular psychiatry. Varying the concentrations of substances normally present in the human body may control mental disease,Science 1968 Apr 19;160(825):265-71.(PMID 5641253) 
- Definition of Orthomolecular medicine at www.orthomed.org Accessed June 2006 and What is Orthomolecular Medicine?, Linus Pauling Inst.
- Age-associated mitochondrial oxidative decay: improvement of carnitine acetyltransferase substrate-binding affinity and activity in brain by feeding old rats acetyl-L- carnitine and/or R-alpha -lipoic acid. Liu J, Killilea DW, Ames BN in Proc Natl Acad Sci U S A 2002 Feb 19;99(4):1876-81 (PMID 11854488)
- Memory loss in old rats is associated with brain mitochondrial decay and RNA/DNA oxidation: partial reversal by feeding acetyl-L-carnitine and/or R-alpha -lipoic acid. Liu J, Head E, Gharib AM, Yuan W, Ingersoll RT, Hagen TM, Cotman CW, Ames BN in Proc Natl Acad Sci U S A. 2002 Feb 19;99(4):2356-61. (PMID 11854529)
- Feeding acetyl-L-carnitine and lipoic acid to old rats significantly improves metabolic function while decreasing oxidative stress. Hagen TM, Liu J, Lykkesfeldt J, Wehr CM, Ingersoll RT, Vinarsky V, Bartholomew JC, Ames BN in Proc Natl Acad Sci U S A. 2002 Feb 19;99(4):1870-5. (PMID 11854487)
- High-dose vitamin therapy stimulates variant enzymes with decreased coenzyme binding affinity (increased K(m)): relevance to genetic disease and polymorphisms. Ames BN, Elson-Schwab I, Silver EA in Am J Clin Nutr 2002 Apr;75(4):616-58 (PMID 11916749) Abstract:As many as one-third of mutations in a gene result in the corresponding enzyme having an increased Michaelis constant, or K(m), (decreased binding affinity) for a coenzyme, resulting in a lower rate of reaction. About 50 human genetic dis-eases due to defective enzymes can be remedied or ameliorated by the administration of high doses of the vitamin component of the corresponding coenzyme, which at least partially restores enzymatic activity. Several single-nucleotide polymorphisms, in which the variant amino acid reduces coenzyme binding and thus enzymatic activity, are likely to be remediable by raising cellular concentrations of the cofactor through high-dose vitamin therapy. Some examples include the alanine-to-valine substitution at codon 222 (Ala222-->Val) [DNA: C-to-T substitution at nucleo-tide 677 (677C-->T)] in methylenetetrahydrofolate reductase (NADPH) and the cofactor FAD (in relation to cardiovascular disease, migraines, and rages), the Pro187-->Ser (DNA: 609C-->T) mutation in NAD(P):quinone oxidoreductase 1 [NAD(P)H dehy-drogenase (quinone)] and FAD (in relation to cancer), the Ala44-->Gly (DNA: 131C-->G) mutation in glucose-6-phosphate 1-dehydrogenase and NADP (in relation to favism and hemolytic anemia), and the Glu487-->Lys mutation (present in one-half of Asians) in aldehyde dehydrogenase (NAD + ) and NAD (in relation to alcohol intolerance, Alzheimer disease, and cancer).
- (PMID: 15681105)
- Riboflavin as a determinant of plasma total homocysteine: effect modification by the methylenetetrahydrofolate reductase C677T polymorphism. Hustad S, Ueland PM, Vollset SE, Zhang Y, Bjorke-Monsen AL, Schneede J in Clin Chem 2000 Aug;46(8 Pt 1):1065-71 PMID: 10926884 The riboflavin-tHcy relationship was modified by genotype (P = 0.004) and was essentially confined to subjects with the C677T transition of the MTHFR gene [homo- and hetero-zygous]. CONCLUSIONS: Plasma riboflavin is an independent determinant of plasma tHcy.
- Einstein said: "We may assume the existence of an aether,; only we must give up ascribing a definite state of motion to it, i.e. we must by abstraction take from it the last mechanical characteristic which Lorentz had still left it." Albert Einstein, "Äther und Relativitätstheorie", Rede gehalten am 5. Mai 1920 an der Reichs-Universität zu Leiden, Springer, Berlin 1920.
- Sander Bais (2005), The Equations. Icons of knowledge ISBN 0-674-01967-9 pp 84-87
- Quantum Field Theory: A Modern Introduction (1993), ISBN 0-19-507652-4 page 336 by Michio Kaku
- Cite error: The named reference
everett57was invoked but never defined (see the help page).
- Cite error: The named reference
dewitt73was invoked but never defined (see the help page).
- Eisenman, Robert (1997). James the Brother of Jesus: The Key to Unlocking the Secrets of Early Christianity and the Dead Sea Scrolls. Viking. pp. pp 62,69. ISBN 1842930265.
- Hugh Everett, The Theory of the Universal Wavefunction (1956), Appendix I. "Monotone decrease of information for stochastic processes" pp 128-129 in The Many-Worlds Interpretation of Quantum Mechanics, Princeton Series in Physics, Princeton University Press (1973), ISBN 069108131X, pp 3-140
- "Whether you can observe a thing or not depends on the theory which you use. It is the theory which decides what can be observed." Albert Einstein to Werner Heisenberg, objecting to placing observables at the heart of the new quantum mechanics, during Heisenberg's 1926 lecture at Berlin; related by Heisenberg in 1968, quoted by Abdus Salam, Unification of Fundamental Forces, Cambridge University Press (1990) ISBN 0521371406, pp 98-101
- Wojciech H. Zurek, Decoherence and the transition from quantum to classical, Physics Today, 44, pp 36-44 (1991)
- Wojciech H. Zurek, Decoherence and the transition from quantum to classical, Physics Today, 44, pp 36-44 (1991); and an updated version from 2003:
- Wojciech H. Zurek, Decoherence, einselection, and the quantum origins of the classical, Reviews of Modern Physics 2003, 75, 715 or 
- Wojciech H. Zurek, Pointer Basis of Quantum Apparatus: Into what Mixture does the Wave Packet Collapse?, Physical Review D, 24, pp. 1516-1525 (1981)
- Wojciech H. Zurek, Environment-Induced Superselection Rules, Physical Review D, 26, pp.1862-1880, (1982)
- Wojciech H. Zurek, Decoherence, Einselection, and the Existential Interpretation (The Rough Guide), Philosophical Transactions of the Royal Society of London A, 356, pp 1793-1820, (1998)
- "There is absolutely nothing mysterious about Afshar's experiment." "And of course, the conventional quantum mechanics is compatible with the principle of complementarity." Lubos Motl at 
- "Bohr would have had no problem whatsoever with this experiment within his interpretation. Nor would any other interpretation of quantum mechanics. It is simply another manifestation of the admittedly strange, but utterly comprehensible (it can be calculated with exquisite precision), nature of quantum mechanics." Bill Unruh at 
- "It was claimed that this experiment could be interpreted as a demonstration of a violation of the principle of complementarity in quantum mechanics. Instead, it is shown here that it can be understood in terms of classical wave optics and the standard interpretation of quantum mechanics." Ole Steuernagel at 
- "Bohr would have had no more problem accounting for the Afshar result than he would in accounting for the aforementioned pre- and post-selection spin experiment, in which the particle's preparation state is confirmed by a nondestructive measurement prior to post-selection." Ruth Kastner at