On 17 Jan 2013, at 15:02, Quentin Anciaux wrote:

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2013/1/17 Bruno Marchal <marc...@ulb.ac.be> On 17 Jan 2013, at 13:32, Telmo Menezes wrote: Hi all, Naive question...Not being a physicists, I only have a pop-science level ofunderstanding of the MWI. I imagine the multi-verse as a tree, whereeach time there is more than one possible quantum state we get abranch. I imagine my consciousness moving down the tree.Suppose Mary performs the Schrodinger's cat experiment in her houseand Joe does the same in his house. They both keep the animals inthe boxes and don't take a peak. Don't tell PETA. They meet for acoffe in a nearby coffeeshop.So now we have four possible universes where Mary and Joe can meet.But from the double slit experiment we know that the cats are bothstill dead+alive in the current universe. Right? So are Mary and Joemeeting in the fours universes at the same time?Let a = alive, d = dead, and the subscript 1 and 2 distinguishes thetwo cats, which are independent. Both cats are in a superposed statedead + alive:(a1 + d1) and (a2 + d2),so the two cats configuration is given by (a1 + d1) * (a2 + d2),with "*" the tensor product.This products is linear and so this give a1*a2 + a1*d2 + d1*a2 +d2*a2.I think it is d1*d2 and not d2*a2.

You are right. Thanks. Bruno

Regards, QuentinMary and Joe don't interact with any cats, so the global state isalso a direct tensor product M * J * (a1*a2 + a1*d2 + d1*a2 +d2*a2), which gives:M * J *a1*a2 + M * J *a1*d2 + M * J *d1*a2 + M * J *d2*a2You can add the "normalization" constant, which are 1/sqrt(2) times1/sqrt(2) = 1/2=1/2 M * J *a1*a2 + 1/2 M * J *a1*d2 + 1/2 M * J *d1*a2 + 1/2 M * J*d2*a2So the answer to your question is yes.To be sure, the normalizing factor does not mean there are fouruniverses, but most plausibly an infinity of universes, onlypartitioned in four parts with identical quantum relative measure.To get the exact "number" of universes, we should first solve themarriage of gravity with the quantum. And with comp, we should alsoderive the Quantum from arithmetic (but that's not true, actually:with comp we have directly the infinities of "universes").Best, Bruno http://iridia.ulb.ac.be/~marchal/ --You received this message because you are subscribed to the GoogleGroups "Everything List" group.To post to this group, send email to everything-list@googlegroups.com.To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com.For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.-- All those moments will be lost in time, like tears in rain. --You received this message because you are subscribed to the GoogleGroups "Everything List" group.To post to this group, send email to everything-list@googlegroups.com.To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com.For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.

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