Hugh Everett: The man who gave us the multiverse

Sep 27, 2014

Image credit: Hugh Everett III Manuscripts/University California Irvine

By Rowan Hooper

Hugh Everett’s many-worlds interpretation of quantum mechanics arose from what must have been the most world-changing drinking session of all time. One evening in 1954, in a student hall at Princeton University, grad student Everett was drinking sherry with his friends when he came up with the idea that quantum effects cause the universe to constantly split.

He developed the idea for his PhD thesis – and the theory held up. According to his work, we are living in a multiverse of countless universes, full of copies of each of us. It was sensational.

Max Tegmark of Massachusetts Institute of Technology has said that Everett’s work is as important as Einstein’s work on relativity. But the leading physicists of the Everett’s day, in particular Niels Bohr, one of the fathers of quantum mechanics, couldn’t stomach it. They couldn’t cope with the idea that every decision we make creates new universes, one for all possible outcomes. Everett had to publish a watered-down version of his idea. Thoroughly disgruntled, he left physics.

What he did next fascinates me, in the light of what he had discovered. Everett joined the Pentagon, and worked in a team calculating potential deaths in the event of nuclear war. His job was to calculate how to maximise the death toll for the Soviets while minimising it for Americans by looking at fallout.

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7 comments on “Hugh Everett: The man who gave us the multiverse

  • The spectacularly lovely-yet-ordinary Professor Brian Cox waxed lyrical about the multiverse on Jim Al Khalili’s excellent R4 show, The Life Scientific.

    I love that we have these great yet modest and ungodly personalities engaging the wider world in the deep satisfactions of rational thought and enquiry.

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  • Thanks Phil. I will enjoy later when all is quite.

    It is great when evolution throws up people like Cox and Attenborough and from my childhood Johnny Ball. He deserves to be brought back into the lives children. I watched him present “The Christmas lectures” a few years back and he has still got it. Some look so awkward on those lectures that my children would lose interest but not with good old Johnny.

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  • I think I know what you mean. I really enjoyed my Physics A-level studies but chose engineering rather than pure science for further education. I still enjoy keeping up to date with the latest theories in the sciences but some of the techniques used are hard to get your head around. Take the procedure called renormalization in quantum electrodynamics (QED), used to avoid a problem of predicted infinite mass of particles. In Hawking’s Grand Design he says:

    “The process of renormalization involves subtracting quantities that are defined to be infinite and negative in such a way that, with careful mathematical accounting, the sum of the negative infinite values and the positive infinite values that arise in the theory almost cancel out, leaving a small remainder, the finite observed values of mass and charge. These manipulations might sound like the sort of things that get you a flunking grade on a school math exam, and renormalization is indeed, as it sounds, mathematically dubious.”

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  • 5
    God-fearing Atheist says:

    “Many Worlds” is usually presented as when I drive down the road to a “T” junction and take a decision to go right, in another world I go left.

    I then think of a container with a gram of hydrogen gas inside. There are 6 * 10 power 23 hydrogen atoms all bounding about exchanging momentum with each other and the sides of the jar. I assume there are at least a billion * 6 * 10 power 23 quantum interactions per second. Does each of them create a new world?

    At the macro level we see a container with a constant internal gas pressure. Trillions of zillions of quantum interactions produce a statistical mean pressure with an immeasurably small standard deviation. So does that mean that while the world is splitting trillions of zillions of billions of times a nanosecond, most of those worlds are identical at the macro level?

    If my decision to turn right is because that is the way to work, then in how many worlds do I turn left? Presumably it depends on my brain state – “alert” or “somewhere else”. But that depends on the sum of my memories and my input, and is itself the statistical mean of billions of trillions of quantum interactions within the molecules of neurotransmitters. In the macro world is my decision inevitable, and therefore the same in all possible worlds?

    So now to chaos (the butterfly effect) and catastrophe theory. One quantum event may push the system into a state where a positive feedback loop forces it into one radically different macro state. (e.g. Pendulum and two magnets). So does that mean the world only splits when a quantum event nudges a chaotic system, or does it happen on every quantum event but most worlds are identical at the macro level?

    Just to complete the chaos, is anyone qualified to comment on this Google tech. talk on QM?

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  • I then think of a container with a gram of hydrogen gas inside. There are 6 * 10 power 23 hydrogen atoms all bounding about exchanging momentum with each other and the sides of the jar. I assume there are at least a billion * 6 * 10 power 23 quantum interactions per second. Does each of them create a new world?

    I understand that it is in the maths of quantum theory, but my well developed commonsense gene, also know as Common Dog @#$%, tells me it doesn’t. With all this new matter and energy being created at every quantum fluctuation, I would think that it has to crash into the laws of conservation of energy sooner or later. If not, then energy is infinite. Everything is infinite. And we know how physics hates infinity. Doesn’t ring true to me.

    I like WYSIWYG that 1980’s computer expression. What you see is what you get.

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  • You might be missing the point of the idea. Stuff is not being created with every event because the stuff is already there. The universe being not just being bigger than it’s possible to imagine: it’s even very much bigger than bigger than that. Nevertheless it isn’t infinite.

    Because there’s so many spare universes available for such frivolous purposes the implications are that situations we normally comprehend as movement or change through time and space don’t really exist. Those are emergent properties of events that span ‘worlds’. Each world differing by a quantum event. One’s consciousness is dispersed in time over a good many moments. Conscious awareness doesn’t exist at any one instant. One instant effectively being 1 universe. The next instant being another. So your idea of self and awareness, sensing, thinking, decisions etc. is really an illusion produced by the transition between ‘worlds’. Aspects of physical reality like the velocity of light being constant irrespective of reference frames is a constraint that follows form the minimum resolvable difference between universes as events span sections of the multiverse. The resolvable and detectable difference between universes being able to be isolated down to a single quantum event. Hence the idea of the quantum computation device. (Apparently on sale at reasonable prices at present – though not yet clear if it actually works. Google are buying some. But possibly may be another variant of the perpetual motion machine. If it actually does work then chances are quite high that we are already living in some kind of matrix simulation of multiverses hosted on a Google server somewhere.

    The multiverse idea explains a lot. Not sure if it’s a useful explanation for physics purposes though. Other than emotionally. Kind of like the Bernoulli effect to explain how flying works with wings: the maths works out OK, but Bernoulli effect fails hopelessly as a satisfying explanation for wing function. Multiverse is a good explanation. But there’s easier maths that already works well on the assumption that only 1 universe is necessary.

    Implications are that anything that is possible must inevitably occur, even if not very frequently approximately duplicated throughout the entire set of universes. What we individuals experience inevitably being only a tiny subset of what is possible. But what is possible can never be infinite. What an individual is aware of is an illusion that results from events appearing to transition multiple universes very rapidly. Like frames of drawings in cartoon animations. The alternative outcomes of a significant decision would be very widely separated because of the myriad quantum events that also occur in addition to the decision outcomes. (Ignoring the impact of the relative lack of free will.) So you could never get anything resembling what happened to Hugh Jackman in the movie ‘The Prestige’.

    Common sense isn’t much help. Also useless are other heuristics like Occam’s Razor. In that entities should not be multiplied more than necessary. The point of the many worlds idea is that entities are multiplied, being necessary for the concept of the theory. That it isn’t common sense that the universe should be other than what people feel it should be like is pretty much exactly how you’d expect it to be. As long as you don’t have any common sense. This particular manifestion of one aspect of the multiverse being where common sense differes substantially from reality. Presumably there are other facets of the multiverse where most people are quite comfortable with the many worlds idea of the multiverse.

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