From klaskey@gmu.edu Mon Mar 20 09:31:39 2006 Date: Mon, 20 Mar 2006 12:31:36 -0500 From: Kathryn Blackmond Laskey To: Henry P. Stapp Subject: Re: Zurek and MU Henry, Thank you for a fascinating exchange! It has helped to clarify some of the problems with MWI, and why "pointer states" and the decoherence basis are not sufficient (at least without much further work) to resolve them. Kathy >Dear Kathy, > >Funny! I was going to refer you to my referee's >report on a follow-up paper by Rubin (quant-ph/0511188) >submitted to Found. Phys. , but decided not to because it was not >about decoherence. > >In any case I attach my reports, which show my >arguments, and Pubin's retreat on the point at >issue. They spell out my argument >in even more detail than elsewhere, in a form directed at an interested >physicists. > >Henry > > > > >On Mon, 20 Mar 2006, Kathryn Blackmond Laskey wrote: > >>Have you seen this? >> >> http://www.citebase.org/cgi-bin/citations?id=oai:arXiv.org:quant-ph/0310186 >> >>Kathy >> >>>Dear Kathy, >>> >>>Please check my 2002 Can. J. Phys. article. It >>>has been widely quoted, with no rebuttal from >>>many-worlders. Its on my website: >>> >>>"The basis problem in many worlds theories" >>> >>>Henry >>> >>> >>> >>> >>>On Sun, 19 Mar 2006, Kathryn Blackmond Laskey wrote: >>> >>>>Henry, >>>> >>>>In MU, page 48, you write: >>>> >>>>"The reason, in brief, why Process 1, or >>>>something that does the same job, seems to be >>>>needed is this: If the universe has been >>>>evolving since the big bang solely under the >>>>influence of the Schroedinger >>>>equation---i.e., Process 2---then every >>>>object and every human brain would by now, >>>>due to the uncertainty conditions on the >>>>original positions and velocities, be >>>>represented in quantum theory by an amorphous >>>>continuum; the center-point of each object >>>>would not lie at a particular point, or even >>>>be confined to a small region, but would be >>>>continuously spread out over a huge region. >>>>Likewise, the state of the brain of every >>>>observer of this object would be a smeared >>>>out conglomeration of many different >>>>classical-type brains. That is, if a human >>>>person were observing an object, whose >>>>center-point, as specified by its quantum >>>>state, were spread out over a region several >>>>meters in diameter, then the state of the >>>>brain of that person would have, for each of >>>>these different locations, a part >>>>corresponding to the observer's seeing the >>>>object in that location. If each of these >>>>parts of the brain were accompanied by the >>>>corresponding experience, then there would >>>>exist not just one experience corresponding >>>>to seeing the object in just one place, but a >>>>continuous aggregation of experiences, with >>>>one experience for each of the possible >>>>locations of the object in the large region. >>>>Thus this theory is often called, quite >>>>rightly, a "many-minds" interpretation: each >>>>person's brain evolves quickly into a smeared >>>>out continuum, and each stream of >>>>consciousness would be part of a continuous >>>>blur of classically describable >>>>possibilities." >>>> >>>>But MWI/decoherence advocates are saying >>>>something different, and you haven't given an >>>>effective argument against it. Specifically, >>>>consider Figure 3 on page 13 of Zurek (2003), >>>>which illustrates how environmental >>>>decoherence eliminates interference between >>>>"Schrodinger cat states." As I understanding >>>>it, MWI advocates argue that in the >>>>decoherence basis, the universe would not be >>>>a giant "smearing," but instead would be a >>>>bunch of spikes like in Figure 13b. Each of >>>>these spikes corresponds to a definite >>>>classical-like reality, and also corresponds >>>>to an awareness in its conscious observers of >>>>that definite classical-like reality. That >>>>is, there are a gajillion instances of "me", >>>>each one perceiving one of the gajillion >>>>"spikes" that exist in the many-minds >>>>Universe. Each me perceives its spike to be >>>>the only spike in existence. At each moment, >>>>each me perceives its spike to be about to >>>>split into a bunch of possibilities. As each >>>>me splits, in the instant it takes for the >>>>off-diagonal humps on the left-hand side of >>>>Figure 13 to evaporate, each copy of me >>>>perceives itself to become only one of the >>>>many possibilities that had formerly been >>>>open. >>>> >>>>The above quote from MU is followed by a >>>>discussion of the need to identify a >>>>countable set of states as measurement >>>>outcomes. You say that CI resolves this issue >>>>by postulating that an intervention by an >>>>experimenter determines the countable set of >>>>possibilities. But this extra postulate is >>>>the very thing the MWI people object to! To >>>>convince a skeptic, you need to give a clear >>>>argument for why the solution of the >>>>decoherence advocates won't work. You don't >>>>do this. >>>> >>>>Zurek says (2002, p. 10): >>>> >>>>"Now, in contrast to the situation described >>>>by Equations (9)-(11), a superposition of the >>>>records of the detector states is no longer a >>>>record of a superposition of the state of the >>>>system. A preferred basis of the detector, >>>>sometimes called the "pointer basis" for >>>>obvious reasons, has emerged. Moreover, we >>>>have obtained it-or so it appears-without >>>>having to appeal to von Neumann's nonunitary >>>>process 1 or anything else beyond the >>>>ordinary, unitary Schrödinger evolution. The >>>>preferred basis of the detector-or for that >>>>matter, of any open quantum system-is >>>>selected by the dynamics." [emphasis added] >>>> >>>>Decoherence advocates say the preferred basis >>>>emerges from the dynamics. You seem to be >>>>making an implicit claim that this is not the >>>>case, but you do not explain what it is about >>>>the derivations in Zurek (2002) that is >>>>missing, incomplete, or incorrect. Until you >>>>have explicitly identified the hole in >>>>Zurek's argument, you have not made the case >>>>that Process 1 is necessary. >>>> >>>>Kathy >> >> > > >Content-id: >Content-type: APPLICATION/MSWORD; NAME=rubin_Mar03_2006.doc >Content-disposition: ATTACHMENT; FILENAME=rubin_Mar03_2006.doc >Content-description: First report > >Attachment converted: iDHARMS:rubin_Mar03_2006.doc (WDBN/MSWD) (001BFF64) >Content-id: >Content-type: APPLICATION/MSWORD; NAME=rubin_Mar_10_2006.doc >Content-disposition: ATTACHMENT; FILENAME=rubin_Mar_10_2006.doc >Content-description: Second report > >Attachment converted: iDHARMS:rubin_Mar_10_2006.doc (WDBN/MSWD) (001BFF65) >Content-id: >Content-type: TEXT/plain; charset=US-ASCII; name=rubin.txt >Content-transfer-encoding: 7BIT >Content-disposition: attachment; filename=rubin.txt >Content-description: Final report > >Attachment converted: iDHARMS:rubin.txt (TEXT/ttxt) (001BFF66)