How to test the many worlds interpretation of quantum mechanics

The many worlds interpretation of quantum mechanics holds that before a measurement is made, identical copies of the observer exist in parallel universes and that all possible results of a measurement actually take place in these universes.

Until now there has been no way to distinguish between this and the Born interpretation. This holds that each outcome of a measurement has a specific probability and that, while an ensemble of measurements will match that distribution, there is no way to determine the outcome of specific measurement.

Now Frank Tipler, a physicist at Tulane University in New Orleans says he has hit upon a way in which these interpretations must produce different experimental results.

His idea is to measure how quickly individual photons hitting a screen build into a pattern. According to the many worlds interpretation, this pattern should build more quickly, says Tipler.

And he points out that an experiment to test this idea would be easy to perform. Simply send photons through a double slit, onto a screen and measure where each one hits. Once the experiment is over, a simple mathematical test of the data tells you how quickly the pattern formed.

This experiment is almost trivial so we should find out pretty quickly which interpretation of quantum mechanics Tipler’s test tells us is right.

Then it boils down to whether you believe his reasoning.

(And not everybody does. When Tipler published his book The Physics of Immortality one reviewer described it as ” a masterpiece of pseudoscience”.)

Let’s hope this paper is received a little more positively than his books.

Ref: Testing Many-Worlds Quantum Theory By Measuring Pattern Convergence Rates

12 Responses to “How to test the many worlds interpretation of quantum mechanics”

  1. devicerandom says:

    Don’t know anything serious about quantum physics (I am a biophysicist), but the tone and the arguments of the communication seem a bit leaning towards quackery. Also, it could just have been written in a rush. I *really* hope Tipler or someone else will find a test for MWI. The scientifical and philosophical consequences would be enormous.

  2. octopus says:

    I don’t see how the author applies the Berry-Esseen theorem in the case of the Born interpretation of quantum mechanics. If we wrote it, it would look like
    | F_B(x,N) – Psi(x)|

  3. octopus says:

    sorry, my post didn’t came out well (forbidden character that cut it in half I guess)
    In fact, I just want to know how the author applies the central limit theorem in the case of quantum mechanics. Doesn’t the Berry-Esseen theorem only concerns the statistics of the average of random variables?

  4. ZEPHIR says:

    From my naive perspective, the many words hypothesis was proposed as one of interpretations of quantum mechanics, therefore I don’t see any reason, why it should differ from other experimental results of QM. After all, we have a mechanical analogy of double slit experiment (DSE) presented already, therefore it’s evident, the QM can be interpreted by common wave mechanics.

    The standard AWT explanation of double slit experiment is, the fast flying particle creates an undulation of vacuum foam around itself by the same way, like the fish flowing beneath the water surface (de Broglie wave). These undulations are oriented perpendicular to the particle motion direction and they interfere with both slits, whenever the particle moves through one of them. The constructive interference makes a flabelliform paths of more dense vacuum foam, which the particle follows preferably being a wave packet, thus creating a patterns at the target.

    Currently I don’t see any reason, why the many word concept should influent the result of DSE, if it should be considered as a standard interpretation of QM at the same time. The Everett’s many worlds concept is alternative interpretation of QM, following from Huygens-Fermat-Lagrange principles of longitudinal wave spreading in particle environments, as such it’s can be explained by AWT mechanically as well and it doesn’t bring any new information into it, by my opinion.

  5. ZEPHIR says:

    By AWT the deBroglie wave or quantum wave itself are real physical artifacts. The fact, they cannot be observed directly by the using of light wave follows clearly from Bose statistics: the surface waves are penetrating mutually, so they cannot be observed mutually.

    What we can observe are just a lensing effect of density gradients (as described by probability function), induced by these waves in vacuum foam by thickening effect during shaking.

  6. Mike Frank says:

    I can’t tell from the short proof summary in the paper whether it is valid, but, based on Tipler’s use of the phrase “observers coupled to the wave function of the quantum system being observed,” I am wondering if he is assuming that the state of the observer is initially entangled with the state of the system (photon) prior to the observation. This would not generally be expected to be the case in a typical experiment with photons aimed at a screen through a slit, since the apparatus generating the photons would not have a coherent relationship with the observers (since both apparatus and human are immersed in a highly decoherent environment), and moreover the photons would not have been observed by the observer prior to their hitting the screen, and so there should be no entanglement between photon and observer; i.e. the join density matrix of the observer and the photon would be expected to be decomposable as a tensor product of density matrices of two independent subsystems. So, if his proof assumes prior entanglement, then I predict that his alternative statistical test will fail in this particular experiment, and that the ordinary statistics would apply. Yet, the MWI can still be true, and the flaw would be in his assumption that the multiple observers present in different branches of the universal wavefunction would necessarily have any prior correlation (entanglement) with the system being observed.

  7. Mike Frank says:

    There is a typo in the middle of my previous comment; “join” should have been “joint.”

    To ZEPHIR: The experiment you cited is fascinating, but the problem with that kind of macroscopic analogy is that the ordinary mechanical surface wave created by N oil droplets suspended on water is a simple superposition of the N droplets’ individual waves on a 2-dimensional space (water surface), or, even if the wave equation is nonlinear, it is still just a function whose domain is simply the two-dimensional (x,y) water surface coordinates. In contrast, the quantum wavefunction of N particles located in a shared 2-dimensional space is a function over a *2N-dimensional* configuration space. The two concepts are not at all the same, the quantum wavefunction is a much more complex type of entity, and so the analogy completely breaks down in cases when there is more than 1 particle. Entangled quantum wavefunction states of more than 1 particle have no analog (no direct one, at least) in the classical mechanical domain, as far as anyone has been able to determine.

  8. Zephir says:

    /*…that kind of macroscopic analogy is that the ordinary mechanical surface wave created by N oil droplets suspended on water…*/

    The article quoted is named “Single-particle interference”. From where you get your “N oil droplets” superposition?

    /*…Entangled quantum wave function states of more than 1 particle have no analog..*/

    Of course, they have. For example, if you split the undulating droplet into two halves, the resulting droplets will undulate “at phase”, i.e. they remain entangled in QM sense.

  9. Mike Frank says:

    Zephir: The point I’m making is, no matter how complex the pattern of water waves may get, the water wave amplitude is always still just a function ranging over only a 2-dimensional manifold of points (x,y). Whereas, with 2 elections confined to a 2-dimensional space, their wavefunction is a joint function over all 4 coordinates, Psi(x1,y1,x2,y2). Already with just 2 particles, the wavefunction has become a more elaborate kind of entity; it can no longer be fully visualized as a wave over real 2-D (or even 3D) space, since its domain is now a 4-dimensional configuration space. You can’t model a function over a 4-dimensional domain with a function over a simple classical 2-D manifold, no matter how fancy the pattern of oscillations in your 2-D wave might get. (At least, no one has showed how to do it yet, as far as I know.) So, these kinds of analogies between Schroedinger waves and classical waves cannot really generalize properly to more than 1 particle. If anyone found a way to reduce N-particle wavefunctions from a D*N dimensional space to a D dimensional one, they would certainly deserve an instant Nobel Prize, because it would not only revolutionize the feasibility of computational quantum physics, but also completely change our understanding of how the universe works. If you think you know a way to do it, more power to you!

  10. Zephir says:

    /*…these kinds of analogies between Schroedinger waves and classical waves cannot really generalize properly to more than 1 particle…*/

    Concerning the quantum -like behavior of oil droplets at the water surface, I don’t understand, why such experiment couldn’t work for 2 or three particles as well – at least conceptually. This doesn’t say indeed, the water surface is direct analogy of QM systems in Hilbert space – but it shows the way, by which the quantum mechanics is connected to classical one via correspondence principle.

    In accordance with this, AWT proposes a nested foam model for modeling of quantum mechanics phenomena in direct analogy to water surface. The foam gets more dense under shaking temporarily, thus mimicking the mass/energy equivalence and probability density function.

  11. […] on the science and religion theme… Frank Tipler on testing the Many Worlds Interpretation Not sure about this… well here’s his homepage and here’s some information about […]

  12. The many-worlds interpretation is by definition experimentally indistinguishable from any other interpretation, because the only effects that would differ from any other interpretation would occur in world inaccessible to our space-time. The view is that every time there seems to be a probability of something in this world, it’s really just how often it does occur in some world. So the only difference is whether these other worlds exist, and no experiment will show that given that they’re not connected space-times. You don’t need to know any of the mathematics to know that. It’s simply a matter of how the many-worlds interpretation is philosophically-based.