Wednesday, September 11, 2013

"19 April 1905" and the Many Worlds Interpretation, or Einstein, that's the wrong physics revolution!

In the "19 April 1905" vignette in Alan Lightman's novella Einstein's Dreams, a man stands on his balcony and ponders whether to go to a woman. He has three options: to stay away, to go to her and start a relationship, or to go to her but not start a relationship. He does each, but in different worlds.

The man on the balcony can do this, not by trick or treachery, but because everyone in this world can do this. Whenever a decision is made, the world splits into three distinct worlds. Eventually, there are an infinite number of worlds [1].

As I was reading this piece, I was struck by its similarity to the Many Worlds Interpretation of quantum mechanics (MWI). The MWI argues that any time a quantum experiment with more than one outcome with non-zero probability is performed, all the outcomes are achieved in different worlds [2].

While there exists only one universe in MWI, there are an infinite number of worlds within the universe. ("Worlds" are defined to be combinations of all macroscopic objects. Macroscopic objects are things like tables, cats, and people.) These worlds are constructed from quantum states corresponding to macroscopic objects, and objects are constructed from the wave functions of elementary particles combined into atoms combined into molecules combined into cells [2].

In equations, that looks like:
To reference a common example, in MWI, Schrodinger's cat is alive in one world and dead in another [2].

What I find most interesting about the integration of this concept into "19 April 1905" is its link with Einstein. (It is, of course, his dream.) Notoriously, Einstein held that quantum mechanics was not a complete theory and not the future of physics. He took issue with the Copenhagen Interpretation of quantum mechanics (the predominant interpretation and an alternative to MWI), saying "I, in any case, am convinced that He [God] does not play dice" [3].

I find the inclusion of a multi-world conception of time interesting, at least as a physics in-joke, though I am not yet sure what (if anything in particular) its purpose is.


References
[1] Lightman, Alan. Einstein's Dreams. New York: Vintage Books, 1993.
[2] Vaidman, Lev. "Many-Worlds Interpretation of Quantum Mechanics." The Stanford Encyclopedia of Philosophy. Edited by Edward N. Zalta. 2008. http://plato.stanford.edu/archives/fall2008/entries/qm-manyworlds/ (accessed September 11, 2013).
[3] Norton, John D. "Einstein on the Completeness of Quantum Theory." Einstein for Everyone. 2013. http://www.pitt.edu/~jdnorton/teaching/HPS_0410/chapters/quantum_theory_completeness/ (accessed September 11, 2013).



5 comments:

  1. I find it interesting that you bring up the question, "What is the purpose of MWI?" I have never thought of MWI in this way. I have only thought about the fact that it might exist, but is essentially very difficult to grasp the fabric of its existence due to obvious reasons, namely, how can you be aware of a world in which you do not exist.

    To ponder the purpose of the existence of many worlds, well, that is a conundrum. I think it might be necessary to first ask, "What is the purpose of one world?" Why is it that only one reality exists in the first place? I find this to be even more worrisome than MWI. With all the amazingness that the Universe holds, would it be so hard to conceive of many worlds existing simultaneously?

    But back to your question: what is the purpose? Some might say that is the is BIG QUESTION. I think that if there were only one reality, then, yes, that would be the BIG QUESTION. But in a multireality existence, the answer my merely be, "because, it's easier to have all possibilities be an outcome then merely one." One outcome is so definite, and I think small little rock we exist in has shown that many possibilities exist. The fact that I can have this conversation in this manner is proof to that.

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  2. During my freshman year I distinctly remember Dr. Seger mentioning in general Chemistry that Einstein’s biggest mistake was that he did not believe in quantum mechanics. He stated the exact quote that you did, Deborah, that Einstein said, “God does not play dice.” I find this topic fascinating; and maybe I’m gullible for thinking that such things could happen. Why couldn’t there be several worlds coexisting from ours? I tend to think of string theory and the hypotheses that there are many numbers of dimensions in the universe. I also think that God can do anything; and if He did play dice, He could load them in any way He wanted.

    Perhaps I just don’t understand the mathematics behind all of it; but if we think of the size of the universe, there is potential for several worlds “out there.” We do not exist and may not ever exist in these worlds due to the vastness of space we must traverse to reach them, yet the infinite expansion of our imaginations is comparable to the infinite expansion of the universe. Perhaps this is a metaphor. Perhaps these two things are related (?).

    I do not have an answer as to what the purpose of the MWI is, but I can see its fulfillment on an individual level. We are forced to make choices in this world. Our choices may not be ideal or may be filled with regret, and the idea that maybe we made a better choice in a different world brings some of us comfort. Our dreams may be the worlds we don’t really exist in, yet we are aware that the dream occurred, even if it wasn’t “real”.

    Have you seen the movie Inception? Do you remember the scene where individuals are pumped full of narcotics and spend most of their time dreaming because their dreams are better than the “actual” world they live in? Can we choose our reality? Or is this simply a way to lie to oneself?

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    1. As usual, when it comes to topics of theology,I have to disagree with you, Cat. Correct me if I'm wrong, but it seems as if you are indicating that the occurrence of every possible quantum result is indicative of God's power. I, on the other hand, would ask: if every quantum result will occur, albeit in different worlds, what need is there of a god to make a decision?

      Perhaps a miracle, if you believe is such things, is only only miraculous in it's inconceivable improbability? A result of the uncertainty principle is that a particle may 'tunnel' through a barrier, apparently without having enough energy to do so. In fact, even macroscopic objects may quantum tunnel, though the odds of doing so are virtually zero.

      As a (facetious) example, perhaps a loved one, stricken with cancer, is suddenly cured. The doctors cannot explain the absolute disappearance of the tumor. Perhaps, in what would be an unimaginably improbable event, the tumor tunneled out? (Correct me if I'm wrong, Lincoln, but my understanding of quantum tunneling says that such an event is physically possible, if limited absolutely by the long-odds).

      I have no doubt that you might consider such an event, even with a physical explanation, to be a miracle. Perhaps God 'set the odds' for that event to occur. But, I would challenge you to consider: what need is there of a god to do such a thing, when all such things were going to happen anyway?

      What about the universe 'next' to ours, in which the quantum event (to tunnel, or not to tunnel) did not happen. Did God's loaded die not deprive those versions of ourselves from the same miracle?

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  3. This is a very interesting topic, and whenever I think of it I cannot help but return to discussions from Stephen Hawking's book, "The Grand Design." I don't know if any of you have read it, but it is a very interesting and very clear-cut explanation of M Theory and corresponding physical theories and laws. I read it many years ago, so I may not remember it correctly (if any of the following seems wrong, then please correct me) but I will try to describe its premise.

    In the book, Hawking discusses his belief that there are an infinite number of universes coexisting side-by-side. Every possible combination of a universe that can exist, does exist. He models these universes as sheets that are aligned parallel to each other side by side for an infinite length, perhaps some type of loop. His main premise is that every so often (on a scale of tens of trillions of years if not more), two of the fluctuating sheets will lightly touch at one point along the sheet. When this happens, each sheet is totally reformed as the "shock waves" travel from the singularity of contact throughout the entire universe. In this way, Hawking tries to describe the Big Bang, and how Big Bangs can and will occur indefinitely in every universe, completely reforming that universe from scratch. In this way, not only does every possible universe exist, but each is repeating itself in an infinite cycle.

    Of course,this theory is on a grand scale and still requires huge amounts of evidence for even a slight validation. However, though it is on the universe level instead of the world level like in MWI, I think it is another interesting model of how time and space can both exist in every possible state, and can repeat itself indefinitely. I wonder if Einstein would have felt the same way about this theory as he did about quantum mechanics? Although this theory is also based on probability, perhaps the grander sense of it allows for some supreme omniscience to oversee all the universes simultaneously, and he alone gets to choose when they collide and begin again.

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  4. When I first read the 19 April 1905 dream I was immediately reminded of Hawkings' multiple universe theory as well. Below I've posted a video that I've watched several times to try and understand different dimensions. In it the idea of an infinite number of universes holding infinite combinations of lives and possibilities exist.

    http://www.youtube.com/watch?v=8Q_GQqUg6Ts

    I believe that people could easily use the idea of time splitting into ever expanding possible scenarios as an excuse to make poor decisions, because surely there exists a universe where they made the better decision. If our universe (or world) is just one of many then why should we truly care about its future? However, I do not see this happening in everyday life. I believe that because we cannot yet travel or see the other dimensions, universes, worlds, etc. we have a very real feeling that our universe if final and all of our actions have irreversible and immediate effects to our lives moving forward. Now if it ever became possible to visit or move between worlds then I believe you would see a fast demoralization of mankind as we did whatever we thought would be satisfying in the short run and then looked to switch into a universe where another us has made all of the right long-term decisions. In this way, I argue that our linear perception of time and the universe is really at the heart of our drive and ability to improve our lives and our world.

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