• [deleted]

I tend to agree that the many worlds interpretation is contentless, as are so called nonlocal hidden variable theories. These may be useful in solving different types of problems, but there are not experimental prospects for testing them.

Cheers LC

  • [deleted]

Einstein might have liked the hypothesis as assurance that the moon is still there whether one looks at it or not. After all, who's to say that a one-way peek from another "world" is not dual to the uncollapsed wave function that we experience as a continuous flow of time in this one? It takes no leap of faith to reconcile a classical experience of time with discrete perceptions so long as one has no investment in that frozen moment; i.e., no fixed frame. In every world of the many universes, any moment is the least of all possible moments of that world. Therefore, time symmetry that remains a local property of our world is impossible in the evolving many-worlds.

Tom

  • [deleted]

Should not Everett be able to continue his work in another Universe?...or is his existence/death here in this Universe, multi_Universal?

If one can die in this Universe, then all Universe's that you split into must calibrate thier wavefunctions to this effect.

In standard shroedinger cat box experiments, what is the difference in weight before observation and after observation?

If shroedingers cat does not exist inside the box (dead), then if the box is placed on an accurate weighing system, the moment you open the box there should be a corresponding increase in the systems weight?

The simple probable outcome, QM speaking, is if one is alive in this Universe, then the probable outcome of you being alive in all other Universe's is zero.

Alive or dead, entangled or seperated?..to be alive in any Universe must be matched with being dead in all other Universe's?

  • [deleted]

Tom,

I think you got it backwards, time symmetry may exist in the many worlds, but along one eigen-selected path time asymmetry is locally apparent.

I think MWI has some working basis with respect to multiverse situations. The grand AdS spacetime, in 27 dimension in the Jordan 3x3 matrix algebra, or maybe 57 dimensions, in an E_{8(8)} model, time is symmetric. However, local regions have within the time arrow direction, say a Z_2 cyclic group of 2 letters, a time direction that is frozen into the local region. Each of these local regions are decoherent sets, similar to what induces the eigen-branching of the Everett MWI.

However, outside of spacetime physics or cosmology I question whether MWI has much content. At least with multi-verse situations there might be metric back reactions associated with generating a nascent cosmology. This would be horrendously difficult to detect, but in principle it could be. Gravity has this classical field realization, which has features not existing in other field interactions. So a standard many world eigen-branching is probably without measurable content.

MWI does imply that we all live a vast number of lives, which I estimate to be around 10^{70}, where this assumes only fluctuation branching inherent in the quanta which make us up. If we include the entire universe things are enormous. This would be 10^{22} quantum collapse events per atom in a thermal context, time 10^{80} atoms in the observable universe, time 10^{23} for the much larger extent of the universe, times the 10^{10} seconds we all live. This might be a grand total of 10^{135} possible life tracks. So this might mean that death is just a sort of restart button on the grand video computer game called the universe, we start over with the first quantum collapse event involved with our conception.

There are also alternate tracks to history, such as where Germany won WWII, the Cuban missile crisis turned into a nuclear conflagration, and General Lee planted the Confederate Stars and Bars over Lincoln's Whitehouse. There are also alternative evolutionary tracks, such as large therapod dinosaus similar to T-rex still live and so forth. None of use can likely exist in any of these alternatives.

This might be extended some if there is some universal contextuality to consciousness. So we might in some nonlocal fashion all be part of one MWI conscious track. Then maybe this is extended to extraterrestrial intelligence elsewhere. Then what about animals? This begins to sound like some Hindu fantasy.

Cheers LC

    • [deleted]

    Lawrence,

    I am looking at MWI as something different than n-dimensional Euclidean space. Because worlds are forbidden to communicate, we can't say anything about time symmetry in any other world than ours. We can say, however, that from a one-way perpective into other worlds, a perspective which other worlds also have of ours -- (i.e., we're all loooking at the same moon) -- event trajectories cannot reverse; time symmetry is local. MWI has to exist in other than a simply connected space.

    Tom

    • [deleted]

    I'm not satisfied with the way that I said that last. I mean that because MWI is based on branching probabilities, irreversibility is built into the event trajectory at any node leading to the many-worlds set -- while preserving time symmetry in our classical universe. If this were not true, continuous information loss would deny us the appearance of the stable universe that we observe. Observers from any of the many worlds should also see the same stable universe as we, through the same one-way mirror that we view it. So as noted, the moon really is there when no one is looking, as Einstein had it.

    Tom

    • [deleted]

    The eigen-branching in MWI is due to observer bias, for fundamentally the universe remains in a superposition of all these branching probability amplitudes. This is what Tegmark says is the "bird's eye" view, where on a fundamental level the world is in a pure quantum state. Yet real observers see the world from a "frog's eye" perspective, and what part of a pure state we observe is in complicated entanglements with parts of the world we have little or no knowledge of. From there the observer bias sets in and the dice outcomes are read. This is the meaning of the eigen-branching of the world. However, on a deep or fine grained level (what the bird's eye sees) the world actually does not branch.

    Cheers LC

      • [deleted]

      Actually, Lawrence, for MWI to hold, the probabilities do have to actually branch, even though the wave function does not collapse. We may read the results of the dice at any arbitrary moment, IOW, but we cannot say anything about a birds-eye view which is inaccessible to us. The observer bias (choice, branching probability) is as real as anything that physics can describe.

      Tom

      • [deleted]

      I suppose there is a different meaning to the use of the word "branch." In the bird's eye view a system becomes entangled with a reservoir of states and so the local observation of some superposed set of states is reduced. This local observation is what we call the collapse. However, the branching is not one where one branch is ontologically real and the others are not. I suppose this is the sense in which I am using the term branching. From a frog's eye perspective one one of the branches is observed, which is a local observation that has the appearance of a collapse. However, if your system has been entangled with some other set of states that entanglement still actually remains.

      Cheers LC

        • [deleted]

        Lawrence,

        Aren't we saying the same thing? The branching probability (entangled state) is real though not observed, and that's all we can make of it.

        Tom

        • [deleted]

        It sounds as if we are meaning the same thing. If we had a superposition of two states in a wave |ψ> = a(1)|1> a(2)|2>, then a measurement is just the coupling of some other set of states, say |> and |-> as spin states that act as a needle so

        |ψ> - -> a(1)|1>|> a(2)|2>|->,

        so the superposition is replaced by an entanglement. So this is a form of branching, and of course this can branch further, for this spin state might has a magnetic moment that couples to a Josephson diode ring, inducing a current (another entanglement) which is then amplified by some electronic (more entanglement) and so forth. Of course this leads ultimately to the Schrodinger cat problem, for we read this out and we do not see the entanglement, but a single outcome. So we are moved along one of the eigen-branches.

        I saw the PBS NOVA program on Hugh Everett, which featured his son who heads up a rock band "The Eels," a bit of an art rock group. I came away with the impression that Hugh worked on the matter of nuclear war almost with an MWI sense of things. It appeared as if he wanted to understand what the eigen-branching was with respect to "war or no war," and our prospects for survival. If the world is ultimately quantum mechanical there is then some world on the grand Markovian eigen-branching tree where the Cuban missile crisis turned into a nuclear war. Maybe Hugh had an interest in making sure we understood what the options were and what the dice throw probabilities were so we might avoid the worst outcomes. The whole program had this sense of melancholy and estrangement to it.

        Cheers LC

        • [deleted]

        We agree.

        One of the facts I see almost never discussed is that our measurement conventions are between mass points. This gets us perturbative results that we can call a continuous function; however, the continuous wave independent of discrete mass points leaves room, however infinitesimal, for events that are real yet beyond measurement. So I tend to agree -- if Hawking did ever actually say the words -- that MWI is "trivially true."

        A non-perturbative theory would bring classical sense back to continuous reality, but there will never be enough "room" for it in our one 4-dimensional world, in principle. Or at least, the principles that current mathematics allows.

        Tom

        • [deleted]

        Tom,

        Clearly nonperturbative theory requires superspace considerations. This is where MWI does manage to have some possible context. With multiple cosmology (multiverse) considerations there are at least some nonlinear gravitational aspects to this. In this setting MWI might have some measurable context, as the eigen-branching might be associated with a unique metric back reaction, which is at least in principle detectable.

        In fact this connects up with solitonic physics on the gravitational brane (D3 or D4 brane) with an underlying quantum physics, but a largely classical structure to spacetime. In other words gravity is not quantized, but is a semi-classical and classical physics which emerges from an underlying quantum field theory. The structure of this type of theory and has connections with 2-dimensional systems like graphene. Much of this stems from well understood physics.

        The k = -1 curvature manifold in two dimensions, the Poincare disk, half-plane or hypersphere, describes by the Gauss-Codazzi a wave motion governed by the sine-Gordon equation

        ∂_{tt}φ - ∂_{xx}φ = sin(φ)

        which is a fascinating equation. This is usually written as

        ∂_{uv}φ = sin(φ),

        for u = (x + t)/2, v = (x - t)/2. This describes the motion of a particle with the line element

        ds^2 = du^2 + dv^2 + 2cos(φ)dudv

        which is the AdS_2 spacetime for the hyperbolic replacement cos(φ) - -> cosh(φ) with the sinh-Gordon equation ∂_{uv}φ = sinh(φ).

        Exact quantum scattering matrix for this sine-Gordon equation was discovered by Alexander Zamolodchikov, which is S-dual to the Thirring model. This is a theory of fermions in two dimensions with the Lagrangian,

        L = ψ-bar(γ^a∂_a - m)ψ - g(ψ-bar γ^aψ)(ψγ_aψ),

        which is a fermionic theory of bosonization -- similar to superconductivity. Zamolodchikov solved this theory and removed the UV divergence with the Bethe hypothesis. The solution is S-dual to the sine-Gordon equation. This points to very deep relationships with respect to gravitation. Gravitation has as its underlying quantum theory a fermionic quantum system with bosonization (a quantum critical point), where gravitation itself is not really quantized.

        This fermion theory, which might be the underlying quantum theory of gravitation (gravitation might not need to be quantized directly beyond a few loop level) is the graded portion of the anyonic field on the two dimensional surface. This is described by a Chern-Simons Lagrangian, which in a more general setting of the 3テ--3 Jordan algebra describes associators with 3 octonions or E_8 groups. This is the possible connection between graphene and these M-theoretic foundations.

        The above fermionic Lagrangian has a bosonization according to Bogoliubov functions. This is a bosonization similar to superfluidity or superconductivity. The interpretation with respect to the emergence of gravity is the onset of decoherent quantum fields in curved spacetime. The emergence of spacetime might then be a phase transition, where the parameter of "disorder" is the scale of quantum fluctuations. This plays the role of temperature if the iHt/ħ is wick rotated i - -> 1 and equated to the Boltzmann term E/kT so the Euclidean time t = ħ/kT serves as the "β" term. So this means the set of quantum fluctuation of the Ferm-Dirac field have a critical point or "attractor," similar to the condition for a Fermi surface, where there is a bosonization.

        Graphene exhibits structure similar to this, and suggests a sort of universality to this sort of physics. In other settings this is also apparent with the quantum phase transition in heavy metal http://arxiv.org/abs/0904.1993 and http://arxiv.org/abs/1003.1728

          • [deleted]

          ARE YOU SERIOUS .....????

          All that is pseudo sciences and even sciences fiction,

          Well and perhaps after the Mtheory and the help) of princeton, really even the medals are falses .

          Ahahaha the string theory and the universe and after what a time machine for the happy new year.

          The strings are falses .And all that is a pure joke .

          MWI and after what it exists an infinite what ....all that is for the second part of sciences community because an under sciences is inserted, the business.

          That's all for the moment.

          Steve

            • [deleted]

            Well Massachussets...it's time to be serious about sciences ,because your are going to be really bad respected in the future .

            Princeton has a real respectability thus at the board, please be rational and forget this under sciences.

            New york new york ??? what are you doing, it's so corrupted , at this point ???? and FQXi of course the message is for you also, you are an innovant platform and you can be rational.

            Regards

            Steve

            • [deleted]

            Steve,

            Dude, chill.

            Tom

            • [deleted]

            Yes, perhaps the extra spatial needs of a nonperturbative theory will turn Goethe's demand for "more light!" into "more room!"

            Tom

            • [deleted]

            That might have a ring of truth to it, if this requires many degrees of freedom. Of course the number of degrees should be conserved. Solitons do have an infinite number of symmetries, but these are largely Pfaffian structures, which are not observables in the proper sense. These symmetries are structures imposed on the group velocity of a linear wave which deforms these waves into nonlinear waves. Which ever is the case the number of degrees of freedom must be within the Bekenstein bound.

            Cheers LC