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.

A rollicking romp through quantum connections

Very few physicists have emphasized the human side of physics as well as Jeremy Bernstein. A veteran physicist and writer who has known many famous physicists of the twentieth century, Bernstein has penned highly readable portraits of Oppenheimer, Bethe and Einstein among others and has written books about nuclear weapons, quants on Wall Street, Bell Laboratories and the German atomic bomb project. In this book he explores the several ramifications of the strange proliferation of concepts from quantum mechanics into popular culture, theater, art, philosophy and cinema. Perhaps this proliferation is not surprising considering the bizarre implications of the actual meaning of quantum theory, but as Bernstein indicates, non-physicists have extended the reach of quantum concepts far beyond what the scientific creators of the theory would have intended.

Bernstein takes us through a diverse variety of topics and characters. He describes the Dalai Lama’s writings in which he draws parallels between Buddhism and quantum theory, and this gives him an opportunity to talk about two central characters in the book, physicists John Bell and David Bohm who the Dalai Lama knew and who played crucial roles in the development of the interpretative parts of the discipline. Bernstein describes the famous conflict between Einstein and Bohr about the meaning of quantum theory and explains Bell’s groundbreaking contributions that argued against Einstein’s belief that quantum mechanics might be governed by some kind of “hidden variables” which we have to discover; Bell showed that any such hidden variable theory would have to involve superluminal communication and would be at odds with the theory of relativity. Later many remarkably precise experiments verified Bell’s ideas, and Bell would almost certainly have received a Nobel Prize had he not died untimely of a stroke.

Bernstein also discusses the extension of quantum theory into non-scientific realms and describes the plays of the playwright Tom Stoppard (writer of “Hapgood” and “Arcadia”), who seems to have incorporated some concepts into his writing. Along the way Bernstein discusses the famous double slit experiment of quantum theory (best discussed in the Feynman Lectures on Physics) which inspired Stoppard and other writers including Princeton philosopher Rebecca Goldstein (author of “Incompleteness”, a fascinating book about Kurt Godel) whose work Bernstein also describes. Bernstein also uses these narrative threads to talk about his own background at Harvard and Princeton where he came in contact with many of the key figures in the development of quantum physics. He has a clear and readable discussion of Bell’s theorem and its background.

The last chapters in Bernstein’s book talk about New Age-type expositions of quantum theory discussed by writers like Gary Zhukov and Fritjof Capra (author of “The Tao of Physics”) who seemingly find many parallels between the philosophical parts of the discipline and Eastern philosophy and mysticism. Bernstein is admittedly not very impressed with these interpretations as many of them sound rather fuzzy and devoid of concrete meaning. Perhaps Bernstein should have also taken a well-deserved jab at the New Age guru Deepak Chopra, whose use of quantum concepts seems to have been divined from thin air.

Readers might be forgiven for Bernstein’s digressions which usually constitute a common part of his writings. For instance his first chapter is about his encounter with poet W H Auden and the philosopher Reinhold Niebuhr which seems to have little bearing on the rest of the book. A chapter on Niels Bohr’s protege, the physicist Leon Rosenfeld, suddenly digresses into how quantum mechanics came in conflict with Soviet Marxism and dialectical materialism, and how Soviet physicists struggled to reconcile physics with their political ideology. A lot of this has to do with Bernstein’s own background and it usually makes for interesting reading, but as in some of his other books, one cannot help shake off the feeling that Bernstein is trying to pack too much into the book and jumping from one topic to another with alacrity. However, I personally enjoy such digressions, and while some others may not, there is still enough interesting material in this slim book to keep most readers with a variety of interests hooked.

A BEAUTIFUL, INFORMAL, AND COMPREHENSIVE ACCOUNT OF QUANTUM HISTORY

Uncertainty: Einstein, Heisenberg, Bohr, and the Struggle for the Soul of Science
David Lindley
Anchor, 2008

One of the best informal histories of quantum physics and its makers that I have come across, and I can say I have read many. Concisely and with passionate enthusiasm, Lindley manages to weave together the essential scientific discoveries, the scores of anecdotes about the famous participants including their personal conflicts and friendships, the philosophical and social implications associated with many quantum concepts, and the political and historical turmoil and connections that accompanied these discoveries. While mainly focused on Einstein, Heisenberg and Bohr, Lindley draws vivid portraits of other pioneers such as Pauli, Dirac, Born, Kramers and Schrodinger. Quantum physics is perhaps the most paradoxical, beautiful, bizarre and important scientific paradigm ever developed. The decade from 1920-1930 was undoubtedly the golden era of physics. Lindley succinctly and engagingly tells us how and why. A must read for history of physics lovers.

MAGIC WITHOUT MAGIC: JOHN ARCHIBALD WHEELER (1911-2008)

Image copyright: NNDB, Soylent communications (2008)

When I heard from a friend about John Wheeler’s death this morning, I grimaced and almost loudly let out an exclamation of pain and sadness. That’s because not only was Wheeler one of the most distinguished physicists of the century but with his demise, the golden era of physics- that which gave us relativity, quantum theory and the atomic age- finally passes into history. The one consolation is that he lived a long and satisfying life, passing away at the ripe age of 96 and working almost till his last day. It was just a few weeks ago that I asked a cousin of mine who did his PhD. at the University of Texas at Austin whether he ever ran into Wheeler there. My cousin who himself is in his fifties said that Wheeler arrived just as he was finishing- after retirement from Princeton university, where he maintained an office right until 2006.

Wheeler was the last survivor of that heroic age that changed the world and he worked with some true prima donnas. He was an unusually imaginative physicist who made excursions into exotic realms; particles traveling backwards in time, black holes, time travel. A list of his collaborators and friends includes the scientific superstars of the century- Niels Bohr, Albert Einstein, Enrico Fermi, Edward Teller and Richard Feynman to name a few. To the interested lay public, he would be best known as Richard Feynman’s PhD. advisor at Princeton.

Wheeler is famous for many things- mentor to brilliant students, originator of outrageous ideas, coiner of the phrase “black hole”, outstanding teacher and writer. My most enduring memory about him is from John Gribbin’s biography of Feynman. Gribbin recounts how Wheeler in his pinstriped suits used to look like a conservative banker, a look that belied one of the most creative scientific minds of his time. The fond incident is about the playful rogue Feynman being summoned into Wheeler’s office for the first time. In order to underscore the importance of his time, Wheeler laid out an expensive pocket watch in front of Feynman. Feynman who had a congenital aversion to perceived or real pomposity took note of this and during their next meeting, laid out a dirt-cheap watch on the table. After a moment of stunned silence, both professor and student burst into loud laughter, laughter that almost always accentuated their discussions on physics and life thereafter. Feynman and Wheeler together derived a novel approach to quantum mechanics that involved particles radiating backwards in time. Wheeler also initiated the discussion of the notorious sprinkler problem described by Feynman in Surely you’re joking Mr. Feynman

John Wheeler was born in Florida to strong-willed and working class parents. After obtaining his PhD. from Johns Hopkins at the age of 21, he joined Princeton in 1938 where he remained all his working life. Princeton in 1938 was a mecca of physics, largely because of the Institute for Advanced Study nearby which housed luminaries like Einstein, John von Neumann and Kurt Godel. Wheeler knew Einstein well and later sometimes used to hold seminars with his students in Einstein’s home. As was customary for many during those times, Wheeler also studied with Niels Bohr at his famous institute in Copenhagen. In 1939 Bohr and Wheeler made a lasting contribution to physics- the liquid drop model of nuclear fission. According to this, the nucleus of especially heavy atoms behaves like a liquid drop, with opposing electrostatic repulsive forces and attractive surface tension and strong forces. Shoot an appropriately energetic neutron into an unstable uranium nucleus and it wobbles sufficiently for the repulsive forces to become dominant, causing it to split. The liquid drop model explained fission discovered earlier. The mathematics was surprisingly simple yet remarkably accurate. Bohr was one of Wheeler’s most important mentors; in his biography he describes how he used to have marathon sessions with Bohr, with the great man often insisting on walking around the department, tossing choice tidbits to Wheeler ambling at his side. Caught up in the recent heated debate about the philosophical implications of quantum theory, Wheeler argued the nature of reality with both Einstein and Bohr.

When World War 2 began, Wheeler like many physicists was recruited into the Manhattan Project. Because of his wide-ranging intellect and versatility, he was put in charge as scientific consultant to Du Pont, who was building plutonium producing reactors at Hanford in Washington state. There Wheeler tackled and solved an unexpected and very serious problem. As the reactors were transforming uranium 238 into the precious plutonium, the process suddenly shut down. After some time it started up again. Nobody knew what was happening. Wheeler who was the resident expert worked out the strange phenomenon in an all-night session. What was happening was that some of the fission products produced had a big appetite for neutrons and were therefore “poisoning” the chain reaction. After some time when these products had decayed to sufficiently low levels, they would stop eating up the neutrons and the reactor would start again. This was one of the most valuable pieces of information gained during plutonium production. Ironically, the omission of this information in a second edition of a government history of atomic energy released just after the war alerted the Soviets to its importance. Working on the Manhattan Project was also a poignantly personal experience for Wheeler; the bomb could not save his brother Joe who was killed in action in Italy in 1944. Wheeler later also worked with Edward Teller on the hydrogen bomb, a decision about which he was fairly neutral because he thought it was necessary at the time to stand up to the Soviets.

After the war Wheeler embarked on a lifelong quest in a completely different field and became a pioneer in it- general relativity. He took up where Robert Oppenheimer had left off in 1939. Oppenheimer had made a key contribution to twentieth century physics by first describing what we now know as black holes. Strangely and somewhat characteristically, he lost all interest in the field after the war. But Wheeler took it up and reinitiated a bona fide revolution in the application of general relativity to astrophysics. As his most enduring mark, he coined the word “black hole” in the 1960s. Wheeler became the scientific godfather of a host of other physicists who became pioneers in exploring exotic phenomena- black holes, wormholes, time travel, multiple universes. His most successful student in this regard has been Kip Thorne whose wonderful book expounds on the golden age of relativity. Hugh Everett, the tragic genius who invented multiple universes and the Lagrange multipliers method for optimization problems before plunging into paranoia and depression, left behind choice fodder not just for science but for science fiction; parallel universes have been a staple of our collective imagination ever since then. In retrospect, Wheeler followed his mentor and did for astrophysics what Bohr had done for quantum theory- he served as friend, philosopher and guide for a brilliant new generation of physicists.

Wheeler was also known as an outstanding teacher. His mentoring of Feynman is well-known, and he devoted a lot of time and care to teaching and writing. Along with his students Kip Thorne and Charles Misner, Wheeler produced what is surely the bible of general relativity, Gravitation, a mammoth book running more than a thousand pages whose only discouraging feature may be its length. The book has served as advanced introduction to Einstein and beyond for generations of students. Wheeler also co-authored Spacetime Physics, an introduction to special relativity which even I have timidly managed to savor a little during my college days. His own autobiography, Geons, Black Holes and Quantum Foam: A Life in Physics is worth reading for its evocation of a unique time of the last century, as well as for fond anecdotes about great physicists.

But many people will remember Wheeler as a magician. Sitting in his office in his pinstriped suits, Wheeler’s mind roamed across the universe straddling everything from the smallest to the largest, exploring far-flung concepts and realms of the unknown. He grappled with the interpretation of quantum mechanics and was an early proponent of the anthropic principle- in John L Casti’s magnificent book Paradigms Lost, Casti quotes Wheeler analogizing observer-created reality with the game in which a group of people asks someone else to guess an object they have in mind by asking questions, except that in the modified version of this game, they let the object be created during the process of questioning. With his mentor Bohr’s enduring principle of complementarity as a guide, Wheeler produced esoteric ideas that nonetheless questioned the bedrock of reality. Wheeler was entirely at home with such bizarre yet profound concepts that still tug at the heartstrings of physicist-philosophers. Only Wheeler could have introduced paradoxical and yet meaningful phrases like “mass without mass”. In celebration of his sixtieth birthday, physicists produced a volume dedicated to him with a title that appropriately captured the essence of his thinking- “magic without magic”.

John Wheeler was indeed a magician. He made great contributions to physics, served as its guide for half a century and motivated and taught new generations to wonder at the universe’s complexities as much as he did. He was the last torch-bearer of a remarkable age when mankind transformed the most esoteric and revolutionary investigations into the universe into forces that changed the world. He will be sorely missed.