From hpstapp@lbl.gov Tue Jul 28 15:41:12 2009 Date: Tue, 28 Jul 2009 15:41:12 -0700 (PDT) From: Henry P. Stapp To: avshalom.elitzur@weizmann.ac.il Subject: Re: No collapse of wavefunction; my Nature letter (fwd) ---------- Forwarded message ---------- Date: Tue, 28 Jul 2009 15:32:01 -0700 (PDT) From: Henry P. Stapp To: avshalom.elitzer@weizmann.ac.il Cc: brucero@ucsc.edu, Charles Stromeyer , dcgrinstein@gmail.com, dualitystan@gmail.com, "Kelly, Edward *HS" , fkuttner@ucsc.edu, David Presti , Stanley Klein Subject: Re: No collapse of wavefunction; my Nature letter (fwd) Dear Elitzer, I really should have run by you this comment of mine about your paper with Dolev, before sending it out to anyone. I do so now, belatedly. I know you understand these things well, so I need 5Ato understand our seeming differences. I will welcome your comments, but am very rushed right now preparing text and power point for a big presentation at a conference in Budapest "Astronomy and Civilization. But I will reply to any comments you may make after my return. We should be able to reach complete agreement. Cordially, Henry P.S. An exposition of my understanding/development of the orthodox interpretation can be found in my book "Mindful Universe: Quantum Mechanics and the Participating Observer" (cf, Ch 13) which details the connection to relativistic quantum field theory, with its advancing sequence of spacelike surfaces upon which the collapses are supposed to occur. ---------- Forwarded message ---------- Date: Tue, 28 Jul 2009 10:56:49 -0700 From: Stanley Klein To: Henry P. Stapp Cc: Charles Stromeyer , dcgrinstein@gmail.com, fkuttner@ucsc.edu, brucero@ucsc.edu, ek8b@hscmail.mcc.virginia.edu, presti@berkeley.edu Subject: Re: No collapse of wavefunction; my Nature letter Thanks Henry, That was very instructive. Do you think that Elitzur doesn't fully understand the collapse ontology?? That would be shocking. Does he really think his logic causes a problem for von Neumann interpretation? Stan On Tue, Jul 28, 2009 at 10:11 AM, Henry P. Stapp wrote: > On Sat, 25 Jul 2009, Charles Stromeyer wrote: > > > > > Hello, > > I have two comments about what Dr. Stapp says below: > > 1)  The main problem with the orthodox Copenhagen (a collapse) > > interpretation > > is that there is an undefined measurement process which converts > > probability functions into non-probabilistic measurements even though > > the > > Copenhagen interpretation asserts that Nature is probabilistic. By > > contrast, > > the Dolev and Elitzur paper shows on page 3 that their result transcends > > ordinary probability theory. > > 2)  What Dr. Stapp says below also agrees with Professor Steven > > Hawking's > > current view of the universe which is that the universe undergoes all > > possible quantum evolutions except that measurements in the present > > determine the past. > > > > Best,Charlie > > > > HPS: The issue is whether or not there is a rationally coherent and > logically consistent understanding of what is going on in nature > that is concordant with all the predictions of quantum > mechanics, and that explains what is actually going on in terms of a well > ordered sequence of collapse events that conform to the rules set forth > in von Neumann's description of the quantum measurement process. > > The Copenhagen interpretation is "a" collapse interpretation, but it is > not the only collapse interpretasion. It is explicitly formulated > as a PRAGMATIC interpretaion that allows human beings to make useful > predictions pertaining to future human experiences on the basis of > information gleaned from past human experiences arising from human probing > actions. > > The "orthodox interpretation", on the other hand, is the name given by > Wigner to the collapse interpretation formulated by von Neumann, It is > interpretable ontologically, in terms of a logically coherent conception > of > what is actually going on. According to this conception, what is going is > a > well-ordered sequence of actual collapse events. This ontological > interpretation is concordant also with Heisenberg's ontological idea of > what > is actually going on. It views the quantum state as not only a compendium > of > the collective effects of the prior collapse events, but also as > "potentia" > (objective tendency) for  the actualization of the next collapse event in > the well-ordered sequence. > > Each actual event has two aspects. First, there is what von Neumann calls > process 1: It is a localized action that puts to Nature a specific > question. This process-1 query is not determineded by any yet-known law or > rule, but its occurrence is demanded by the orthodox interpretation. > Such queries are demanded also by the Copenhagen interpretation, where > each > is called a "free choice on the part of the experimenter". It is the > experimenter's choice of which experiment he will perform: > which action he will take. > > Nature returns an answer that eliminates certain localized parts of the > prior state. This local action induces a global change to a new quantum > state of the universe. Each successive state in the well-ordered sequence > is > defined over all spacetime, and satisfies the Schroedinger > equation EVERYWHERE AND AT All TIMES. The objective tendencies for the > next > event in the well-ordered sequence are specified by the new state. > > The quantum nonlocal action at a distance indicated by Bell's theorem > (and proved in certain generalizations thereof) is entailed by these > dynamical rules. The relativistic requirements of relativistic quantum > field > theory are also entailed. Each collapse event recreates the past, insofar > as > the past is the basis of the causal objective tendencies for the future. > > The analysis of D&E (Dolev and Elitzer) singles out the subset of events > in > which the photon in the Mach-Zehnder interferometer is detected > in the detector d, which is the detector at which there is normally > complete > destructive interference, and hence no detection. But in the D&E > experiment > a sequence of three devices is placed in one segment of the photon's path, > namely the v leg that emerges from the first beam splitter, which splits > the > incident photon 'gamme' into |v> +i|u>. Each > of the three devices, j,  has an atom in a superposed atate > (|Z(j+)> + |Z(j-)>/(root 2), with the |v> part of the photon beam passing > sequentially through each component |Z(j+)>, missing each of the > components > |Z(j-)>. The |u> component of the photon lies far away from > the three atoms, but is nevertheless multiplied by the (undisturbed) state > of the three atoms. > > D&E "discard all the cases in which absorption has occurred." > The cases D&E discard are those in which the v beam encounters > an atomic state |Z(j+)>: Thus absorbtion is assumed to occur if > beam v encounters a |Z(j+)>. > > The part of the full quantum state in which the photon ends up > in detector d is then straightforwardly, > > Psi(d) = -i|d>[Product over j of (|Z(J+)>+|Z(j-)>) >              -|Z(1-)>|Z(2-)>|Z(3-)>]/4 root 2 > > This formula simply expresses the fact that quantum state that survives > photon annihilation at d will come solely from the u part of photon, and > only from the part of the u part that is not cancelled at d by the > desructive interference from the part coming to d via v, namely > |Z(1-)>|Z(2-)>|Z(3-)>: each of the eight contributions > from the u path contributes to the event at d except the one that > corresponds to the v path that passes "unaffected" through the three > devices. That one contribution associated with the u path will get > cancelled out by the v contribution, and not contribute to |d>. The other > seven parts associated with the u part of the quantum state will > contribute, > undiminished. > > The formula given above is pure mathematics, and its interpretation > is obtained by examining how it arose. > > But now D&E say "Let us measure atom > 2's spin, and proceed only if is found to be |Z(2+)>. > > Comparison with what went earlier shows that they mean that AFTER the > detection at d has occurred they measure the Z component of atom 2, and > consider the subset of cases in which the observed state is |Z(2+)>. > > But the collapse that occurred at the detection event at d has created > a new state, by eliminating the part that corresponds to the non-occurring > |c>. > > This state that survives the collapse at d comes from the u part > of the photon beam, and for this part the photon is not interacting > with the atoms. Thus it is neither surprizing nor problematic that > picking out the |Z(2+)> part leaves the other two parts unaffected. > > This global collapse is a crucial basic feature of the orthodox collapse > interpretation. It does not prevent the actual collapse events from > occurring in some well defined order. It makes predictions dependent in > general upon the order of timelike separated collapse events, but > independent of the order of spacelike separated events. This dependence > of future objective tendencies upon which collapses have already occurred > may be in "defiance of ordinary temporal notions".  But that does not > prevent the actual collapse events from occurring in a well-defined > sequential order, and it does not prevent the orthodox ontological > interpretation from being rationally coherent, given the basic assumption > that the collapses change the global state. > > Placing a photon-absorbing object B in the path v, just after the third > atom creates, of course, a new global situation. Absorption of the photon > at B may or may not occur. If it does, then there will be no detection at > d. > If absorption at B does not accur then the full contribution at d arises > from the u contribution alone, without any cancellation. In either case > the > insertion of B changes the global situation. But the various results are > all > rationally understandable in terms of the premises of the orthodox > ontological interpretation, and a well-ordered sequence of collapse > events. > The arguments of D&E do not demonstrate any inconsistency in this > collapse interpretation. > > > > > > > > > Hello, > > > > Thank you Dr. Stapp for sending me your paper. I do not have a > > > > problem > > > > with your particular theory of quantum mind, but there is a major > > > > problem with collapse interpretations of the wavefunction which is > > > > that > > > > they > > > > contradict experimental reality. Please see page 4 of the paper I > > > > cite > > > > below in my new letter today that I sent this morning to the journal > > > > Nature. > > > > > > HPS: The claim on page 4 of Dolev and Elitzur (D&E) that you refer to > > > is > > > undoubtedly this: > > > > > > "Ordinary concepts of motion, which remain implicit in both "guide > > > wave' and 'collapse' interpretations are inadequate to explain > > > this behaviour" > > > > > > The ordinary concepts of motion are certainly NOT implicit in the > > > orthodox > > > 'collapse' interpretation. And the associated implication that the > > > arguments of D&E somehow rule out 'collapse' interpretations is > > > certainly > > > wrong! > > > > > > This claim of D&E arises from a comparison of the (unambiguous) > > > predictions of (the collapse-based) orthodox quantum theory in two > > > different experimental situations. As Bohr repeatedly emphasized, > > > one must always consider the "whole experimental situation": > > > changing the experimental condition anywhere creates a new global > > > situation. > > > > > > The two situations compared by D&E involve inserting or not inserting > > > into the lower  photon beam of their Figure 2, just after this beam > > > has > > > passed the three atom in Figure 2, an absorbing object B. This > > > comparision > > > generates paradoxes, insofar as one's thinking is restricted to > > > classical > > > ideas about motion. But it entails no conceptual problem for orthodox > > > collapse-based quantum mechanics. > > > > > > Recall that in relativistic quantum field theory the Schroedinger > > > state > > > rho(sigma) is defined on a spacelike surface sigma. Each new collapse > > > event is associated with a slight local forward push, > > > sigma(i)-->sigma(i+1), > > > of the surface upon which the state is defined, coupled with a > > > reduction > > > rho-->P rho P, where P is a projection operator that acts over the new > > > part of the surface. But if the state contains entangled parts, > > > generated by some past localized interaction between some now-distant > > > parts, then the local action of P can produce changes in parts of rho > > > located on faraway parts of sigma(i+1). This produces the celebrated > > > nonlocal aspects of relativistic quantum field theory. > > > > > > One can pictorially "understand" this nonlocal action-at-a-distance by > > > starting from the rho on the new surface sigma(i+1), and > > > > > > "by running the Schroedinger equation backward in time, generating > > > the past that leads deterministically to the correlated state observed > > > on > > > sigma(i+1)." > > > > > > The correlations observed on sigma(i+1) will then appear to be have > > > been generated by a local interaction in the past, and causally > > > carried > > > to > > > far-apart regions by spreading waves. Each reduction event will then > > > be viewed as changing the initial conditions of a deterministically > > > evolving universe. > > > > > > This way of 'picturing' the causal structure neatly 'explains' the > > > effects of nearby actions upon a distant features---and also Bohr's > > > remark---within the collapse-based interpretation. But this > > > 'explanation' certainly does not conform to the normal idea of > > > causation, > > > which do not allow a present choice of action to effectively change > > > the > > > past. > > > > > > This way of understanding the causal structure effectively > > > universalizes > > > the explanation of Wheeler's delayed-choice experiments. > > > In quantum mechanics our present choices routinely influence the past. > > > > > > The collapses also explain wave-particle duality: the action > > > rho--> P rho P can suddenly reduce the spread of a field of > > > potentiality associated with, say, an electon from a very large > > > region to a very tiny region. > > > > > > > > > > Also, I would please like to know your opinion of the theory called > > > > > > Quantum Darwinism which asserts that classical reality evolves from > > > quantum reality via some concept of natural selection: > > > > > > > > http://en.wikipedia.org/wiki/Quantum_darwinism > > > > > > > > > > > > > I agree that  presence of classical concepts in our perceptions > > > of reality arises from natural selection, and involves environmental > > > decoherence. These factors influence the evolving form of the > > > projection > > > operators P that occur in the basic collapse action rho-->P rho P. > > > > > > A key point is the causal efficacy of the von Neumann Process 1 > > > choices of the operators P. The form of P can evolve by natural > > > selection > > > only of it is causally efficacious in the physical would. This causal > > > efficacy is brought about within the orthodox collapse form of quantum > > > mechanics by the quantum Zeno effect. > > > > > > These matters are discussed in the Budapest Lecture > > > I sent to you, The entire discussion is within the orthodox > > > collapse framework. > > > > > > Zurek tries to avoid introducing collapses, so his task in > > > recovering all of the beautiful results of orthodox quantum > > > mechanics is very a difficult---and I believe impossible--- > > > one. It is better to build upon the profound insights of the > > > founders, and the wonderful mathematical structure they discovered, > > > rather than trying to circumvent them. > > > > > > > > > > > > > > > > Sir, > > > > > > > > I have just read the interesting new letter by Kirchmair et al. > > > > entitled > > > > "State-independent experimental test of quantum contextuality" in > > > > Nature 460, p.494-497 (23 July 2009). However, from what I can tell, > > > > classical non-contextuality was already ruled out by this previous > > > > paper > > > > from eight years ago by S. Dolev and A.C. Elitzur entitled > > > > 5A"Non-Sequential Behavior of the Wave Function" which shows that > > > > the > > > > wavefunction of quantum mechanics is fundamentally non-sequential > > > > rather > > > > than sequential: > > > > http://arxiv.org/abs/quant-ph/0102109 > > > > > > > > Sincerely,Charlie Stromeyer Jr. > > > > cstromeyer@post.harvard.edu > > > > > > > > > > >