Strange Parallels: Choice Histories Found in Physics And Culture
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Certain pivotal events in history seem to start a schism with time, separating what really happened from countless other “what ifs.”
World War II, with its succession of controversial decisions, included many such pivotal moments, culminating in President Truman’s buy to start atomic bombs on Japan. Physicists were sharply divided about this decision: Some such as Albert Einstein regretted the bomb’s development – given that the Germans, since it proved, had made little progress – and others, such as John Wheeler, one of its many creators in the Manhattan Job, argued that it will have been built and launched earlier to end the war sooner and save an incredible number of lives. Wheeler’s argument was personal; his more youthful brother Joe, a soldier in fight, had delivered him a postcard with the plea “hurry up!” shortly before getting killed.
Speculative fiction writers mined the ambiguities of World War II with superb passion, producing such seminal works as The Garden of Forking Paths by Jorge Luis Borges (who wrote the piece near the start of war, and placed it in World War I), and The Man in the High Castle by Philip K. Dick (who produced his bold eyesight of an alternative closing to WWII with Axis victors extended after its legitimate finale). Each writer pondered time as a maze of ever-splitting paths, where though we eventually find ourselves on one succession of strands, there will be countless other choices that each have their own truth.
Such visions of temporal labyrinths were revolutionary at the time, given that the traditional novel offered an individual linear chronology, from opening to climax and denouement. Indeed classical physics echoed such a uniform, single-stranded view of time, positing that the life span of a particle was uniquely dependant on its initial conditions and selection of forces acting on it. Whether a character in a Victorian novel or a classical human body subject to Newtonian dynamics, its fate was typically predictable, given complete knowledge of the other players involved. The lesson appeared to be that while we might wonder “imagine if?,” the trajectories of all things were truly as inevitable as the ticking of an eternal clock.
By natural coincidence, roughly the same time that Borges penned his impressive literary speculations about time being truly a labyrinth of possibilities, Richard Feynman, a young graduate of MIT, joined John Archibald Wheeler at Princeton in creating a revolutionary fresh vision of quantum mechanics. Their research together occurred during the brief window of opportunity between the start of war in European countries in Sept. 1939 and American involvement following the Pearl Harbor strike in Dec. 1941. Aiming to getting a quantum method for describing how electrons interact with the other person through their mutual electromagnetic power, they posited the surprising outcome: a mixture of all physically possible ways at once. Wheeler, with his pension for coining fresh expressions, dubbed it “sum over histories.” While their joint project never found fruition, Feynman dusted off the theory several years soon after in his Nobel-Prize-winning description of quantum electrodynamics.
Rather than delving in to the technical particulars, sum-over-histories could be understood informally by considering what sort of mapping application calculates unique possibilities for a trip: one route might involve freeways, for example, another more scenic byways, and a third way city streets. Normally, such an app supplies the travel time for every of the alternatives separately. If, on the other hand, it were programmed to take a sum-over-histories approach, it could weigh each route regarding to its likelihood, and provide a travel time prediction based after a combination of the options.
Feynman, who disliked philosophical speculation, never referred such a blend due to “parallel universes” or “solution realities.” Rather, he found it as a kind of accounting scheme that treated the various alternatives as part of the vital haziness of quantum mechanics. The theory offered powerful predictions, and that is what mattered in his look at.
A later scholar of Wheeler, Hugh Everett III, who completed his Ph.D. at Princeton in 1957, will be a lot more fanciful and speculative in his very own quantum eyesight. Everett addressed the question of what goes on during the procedure for measuring the properties of a subatomic particle, such as an electron. In line with the orthodox interpretation of quantum mechanics, as championed by Niels Bohr and others, it’s the conversation with the observer and the observer, along with an factor of probability, that decides what goes on up coming. Einstein rebelled against that view, famously exclaiming that “God does not roll dice!” and jesting that if a human being observer is necessary for quantum measurement, you will want to a mouse instead? Alert to Einstein’s critique, Everett set out to find a excellent interpretation that required no “dice-rolling” or human being intervention.
Under Wheeler’s guidance, Everett developed a novel way of looking at quantum mechanics that involved the bifurcation of the universe into different branches whenever a measurement occurred. Each branch will be identical, aside from a different result of the measurement in question. The observer’s personal timeline would split as well, with each copy believing that the results he or she recorded was the true one.
While Bohr was dismissive of Everett’s hypothesis, another physicist Bryce DeWitt (the editor of the volume to which Everett and Wheeler submitted the paper) was intrigued. DeWitt was curious, on the other hand, how Everett justified the splitting of truth if nobody ever felt it. Everett replied that the anti-Copernicans said the same about the planet earth moving around the sun; nobody sensed that either. DeWitt was hooked, and put in much of his later years popularizing Everett’s thought, which he dubbed “THE COUNTLESS Worlds Interpretation of Quantum Mechanics.” The idea still has its strong adherents, notably physicists David Deutsch and Max Tegmark (who wrote a bit for 13.7 in October).
The idea of parallel universes and alternative histories, once confined to mere rumination about shed opportunities and speculative fictional scenarios is currently a company part of science – at least in the Feynman construction of sum-over-histories, and perhaps in the Everett hypothesis that reality itself splits.
So the the next time you gamble your life’s savings on a horse that lies down on the path to the finish line or on a lottery ticket that is just one digit off from the winning number, revel in all the alternative versions of yourself celebrating a more auspicious outcome.
Paul Halpern can be an author and a professor of physics in the University of the Sciences in Philadelphia. His latest reserve, The Quantum Labyrinth: How Richard Feynman and John Wheeler Revolutionized Time and Reality, was posted in October. You could find him on Twitter at @phalpern.