Friday, June 25, 2010

Parallel universes, parallel lives

"Parallel Worlds, Parallel Lives" is a documentary about Hugh Everett, the brilliant and troubled physicist who conceived the idea of parallel universes, which have become a staple of science fiction ever since and are now being taken seriously even by serious scientists.

Everett received his PhD. from Princeton in the 1950s with John Wheeler. At the time the prevailing view of what happens when you observe a quantum system was the Copenhagen Interpretation which said that until you observe a quantum system it exists in a superposition of states; the wavefunction of such a system suddenly "collapses" when you observe it. This of course led to several dilemmas and paradoxes, the most famous one being Schrodinger's Cat. Several questions arose; when exactly does the wavefunction collapse? Who can collapse it? Everett bypasses the whole problem by assuming that quantum systems simply exist in many different states but in separate universes and you observe one of them. Thus the wavefunction does not collapse at all. This of course sounded fantastic, implying that at every moment, there is a copy of you for instance that splits into infinitely many copies in infinitely many universes. However, it did seem to provide a simple way out of Schrodinger's cat-type problems. The "many-worlds interpretation" of quantum mechanics has fascinated, troubled and interested scientists and laymen alike ever since.

Unfortunately, Bohr's "gospel" prevailed among physicists, and Bohr strongly disagreed with Everett in a meeting that Wheeler had set up between them. Disappointed and with a family history of depression, Everett left academia for good. He spent the rest of his life doing top-secret work for the government, coming up with algorithms and computer programs for modeling nuclear war. He apparently was very influential in suggesting nuclear weapons policy which the government adopted and several of his reports are still highly classified. One of the concepts he pioneered was the Lagrange multipliers method, a key tool in solving differential equations with constraints in diverse disciplines. He died suddenly of a heart attack in the 1970s. Everett had a drinking problem and a tragic family life. He was very distant from his children. His son who is the main subject in the documentary says that the only time he touched his father physically was after he died and the dead body had to be moved. Everett's daughter committed suicide, writing a bizarre suicide note saying that she was going to meet her father in a parallel universe.

The documentary is a NOVA documentary on PBS. It's about Everett's son, the musician Mark Everett (who seems to be quite successful with his band "The Eels") who sets out on a journey to Princeton, the Pentagon, Austin, Cambridge etc. to find out more about his father and speaks to such people as Charles Misner and David Deutsch. On the way he learns some quantum mechanics and gets to know his father much better. In the end he feels much closer to his father and seems to have finally received closure. It was rather touching to be honest and there is a sense of satisfaction in his son finally seeming to be at peace.

Note: A rather expensive biography of Everett has just come out. A cheaper, free version is a short Scientific American piece on him.

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