And speaking of multiverses, this was just published on the Scientific American website<http://www.scientificamerican.com/article.cfm?id=multiverse-the-case-for-parallel-universe> .
*In the August issue of*Scientific American,* cosmologist George Ellis describes why he's skeptical about the concept of parallel universes. Here, multiverse proponents Alexander Vilenkin<http://www.scientificamerican.com/article.cfm?id=multiverse-the-case-for-parallel-universe&WT.mc_id=SA_WR_20110727#> and <http://www.scientificamerican.com/article.cfm?id=multiverse-the-case-for-parallel-universe&WT.mc_id=SA_WR_20110727#> **Max Tegmark<http://www.scientificamerican.com/article.cfm?id=multiverse-the-case-for-parallel-universe&WT.mc_id=SA_WR_20110727#> offer counterpoints, explaining why the multiverse would account for so many features of our universe—and how it might be tested.* *-- Russ Abbott* *_____________________________________________* *** Professor, Computer Science* * California State University, Los Angeles* * Google voice: 747-*999-5105 * blog: *http://russabbott.blogspot.com/ vita: http://sites.google.com/site/russabbott/ *_____________________________________________* On Wed, Jul 27, 2011 at 12:54 PM, Russ Abbott <russ.abb...@gmail.com> wrote: > I just looked at *Theory of Nothing* on > Amazon<http://www.amazon.com/Theory-Nothing-Russell-Standish/dp/1921019638>. > Two very nice reviews. Amazon's "Look Inside" doesn't show much, but the > book looks very much worth reading. The Introduction talks > about Schrodinger's cat. It had never occurred to me that the cat *always > *experiences a boring hour and then comes out alive--at least according to > the Many Worlds View of QM. It's on my reading list. > > *-- Russ Abbott* > *_____________________________________________* > *** Professor, Computer Science* > * California State University, Los Angeles* > > * Google voice: 747-*999-5105 > * blog: *http://russabbott.blogspot.com/ > vita: http://sites.google.com/site/russabbott/ > *_____________________________________________* > > > > On Tue, Jul 26, 2011 at 3:13 PM, Grant Holland <grant.holland...@gmail.com > > wrote: > >> Exciting, Russ. I've downloaded your 2004 >> paper<http://arxiv.org/pdf/physics/0001020v6>, >> and will take a look. >> >> Thanks, >> Grant >> >> >> On 7/26/11 3:16 PM, Russell Standish wrote: >> >> Of course, I published a paper in 2004 (Why Occams Razor) doing >> essentially the same thing (I expanded on this somewhat in my 2006 >> book, Theory of Nothing). >> >> I would also say, that Lucien Hardy did something similar in 2001 >> (Quantum theory from five reasonable axioms). Also, there have been >> other works linking the uncertainty principle to the Cramer-Rao >> inequality from information theory. >> >> I expect this current paper (when I finally get around to read it), will be >> equivalent to what I've done. Ultimately, it may come down to history >> which method is preferred, or if some uber-clear version is presented >> (like Dirac did to Schroedinger and Heisenberg's theories). >> >> It would be all the more remarkable if this approach was fundamentally >> different. >> >> All I have to say now... >> >> On Tue, Jul 26, 2011 at 10:37:46AM -0700, Russ Abbott wrote: >> >> I expected this to have more of an impact than it seems to be having. What >> am I missing? >> >> *-- Russ Abbott* >> *_____________________________________________* >> *** Professor, Computer Science* >> * California State University, Los Angeles* >> >> * Google voice: 747-*999-5105 >> * blog: *http://russabbott.blogspot.com/ >> vita: http://sites.google.com/site/russabbott/ >> *_____________________________________________* >> >> >> >> On Mon, Jul 25, 2011 at 2:50 PM, Russ Abbott <russ.abb...@gmail.com> >> <russ.abb...@gmail.com> wrote: >> >> >> From APS Physics <http://physics.aps.org/articles/v4/55> >> <http://physics.aps.org/articles/v4/55>. >> >> We know how to use the “rules” of quantum physics to build lasers, >> microchips, and nuclear power plants, but when students question the rules >> themselves, the best answer we can give is often, “The world just happens to >> be that way.” Yet why are individual outcomes in quantum measurements >> random? What is the origin of the Schrödinger equation? In a paper >> [1<http://physics.aps.org/articles/v4/55#c1> >> <http://physics.aps.org/articles/v4/55#c1>] >> appearing in Physical Review A, Giulio Chiribella at the Perimeter >> Institute inWaterloo, Canada, and Giacomo Mauro D’Ariano and Paolo >> Perinotti at the University of Pavia, Italy, offer a framework in which to >> answer these penetrating questions. They show that by making six fundamental >> assumptions about how information is processed, they can derive quantum >> theory. (Strictly speaking, their derivation only applies to systems that >> can be constructed from a finite number of quantum states, such as spin.) In >> this sense, Chiribella et al.’s work is in the spirit of John Wheeler’s >> belief that one obtains “it from bit,” in other words, that our account of >> the universe is constructed from bits of information, and the rules on how >> that information can be obtained determine the “meaning” of what we call >> particles and fields. >> ... >> >> They assume five new elementary axioms—causality, perfect >> distinguishability, ideal compression, local distinguishability, and pure >> conditioning—which define a broad class of theories of information >> processing. For example, the causality axiom—stating that one cannot signal >> from future measurements to past preparations—is so basic that it is usually >> assumed a priori. Both classical and quantum theory fulfil the five >> axioms. What is significant about Chiribella et al.’s work is that they >> show that a sixth axiom—the assumption that every state has what they call a >> “purification”—is what singles out quantum theory within the class. In fact, >> this last axiom is so important that they call it a postulate. The >> purification postulate can be defined formally (see below), but to >> understand its meaning in simple words, we can look to Schrödinger, who in >> describing entanglement gives the essence of the postulate: “Maximal >> knowledge of a total system does not necessarily include maximal knowledge >> of all its parts.” (Formally, the purification postulate states that every >> mixed state ρA of system A can always be seen as a state belonging to a >> part of a composite system AB that itself is in a pure state ΨAB. This >> pure state is called “purification” and is assumed to be unique up to a >> reversible transformation on B). >> >> Chiribella et al. conclude there is only one way in which a theory can >> satisfy the purification postulate: it must contain entangled states. (The >> other option, that the theory must not contain mixed states, that is, that >> the probabilities of outcomes in any measurement are either 0 or 1 like in >> classical deterministic theory, cannot hold, as one can always prepare mixed >> states by mixing deterministic ones.) The purification postulate alone >> allows some of the key features of quantum information processing to be >> derived, such as the no-cloning theorem or teleportation >> [7<http://physics.aps.org/articles/v4/55#c7> >> <http://physics.aps.org/articles/v4/55#c7>]. >> By combining this postulate with the other five axioms, Chiribella et al. >> were >> able to derive the entire mathematical formalism behind quantum theory. >> >> >> >> *-- Russ Abbott* >> *_____________________________________________* >> *** Professor, Computer Science* >> * California State University, Los Angeles* >> >> * Google voice: 747-*999-5105 >> * blog: *http://russabbott.blogspot.com/ >> vita: http://sites.google.com/site/russabbott/ >> *_____________________________________________* >> >> >> >> ============================================================ >> FRIAM Applied Complexity Group listserv >> Meets Fridays 9a-11:30 at cafe at St. John's College >> lectures, archives, unsubscribe, maps at http://www.friam.org >> >> >
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