Sidney Coleman

By Sean Carroll | November 19, 2007 5:43 pm

coleman.jpg Very sad to report that Sidney Coleman passed away yesterday. Sidney, a professor at Harvard, was one of the greatest theoretical physicists of recent times. He doesn’t share the name recognition among the general public that some of his contemporaries have — he was always more interested in the deep underlying principles of quantum field theory than in any particular model of the universe — but no student of high-energy physics could help but be deeply influenced by his thinking, both through his research and his famous Erice lectures. He was an invaluable resource when I was a grad student at Harvard, both through his quantum field theory course and through many hours spent in his office pestering him with specific questions. At my wedding just a couple of months ago, some of the happy-memory-sharing involved trading our favorite Sidney quotes; “Modesty forbids me but honesty compels me” was my personal choice.

Sidney’s papers were not like anyone else’s. One of his classic quotes, from a paper with de Luccia on “Gravitational Effects on and of Vacuum Decay“:

The possibility that we are living in a false vacuum has never been a cheering one to contemplate. Vacuum decay is the ultimate ecological catastrophe; in the new vacuum there are new constants of nature; after vacuum decay, not only is life as we know it impossible, so is chemistry as we know it. However, one could always draw stoic comfort from the possibility that perhaps in the course of time the new vacuum would sustain, if not life as we know it, at least some structures capable of knowing joy. This possibility has now been eliminated.

Plenty of people aspire to be profound and playful at the same time; Sidney could pull it off, and had the technical chops to back it up.

Sidney had been sick for the last few years. In 2005 there was a conference in his honor, which arguably featured the greatest concentration of physics talent in recent memory; I wasn’t there, but Jacques Distler blogged a bit about it.

Physics will be a little bit duller without him.

  • Fine Structure

    Sad thing!.. I am reading QFT from his lecture notes as I heard this!

  • none-of-the-above

    Sidney’s erudition and wit were legendary. But it was his patience and generosity with students (of all ages) that made him truly revered. This is a very sad day for anyone who had the priviledge of knowing him. My condolences to his family on their loss.

  • John Farrell

    Prof. Coleman was kind enough some years back to let me interview him for a piece on quantum physics for the American Spectator (Chris Caldwell was the editor at the time) that, alas, was never published. (Don’t get me started in conservative magazines and science….)

    Prof. Coleman had a great sense of humor. One of my favorite quotes from him occurred during the 1989 World Science Fiction convention in Boston. On a panel about quantum physics, he said,

    “If you mentioned quantum physics at a cocktail party ten years ago, no one would invite you back. More recently a woman approached me and said, ‘Isn’t quantum physics just what Eastern mystics have been saying for the last two thousand years?’ I had to summon every ounce of dignity and told her, ‘No.!'”

    “Reality is blue, and clouds fly through it.”

  • Mark

    A great loss. I didn’t know him well, but encountered him a number of times as a graduate student and as a postdoc and learned something every time.

  • Typo Guy

    Worth fixing in a quote: “Modestly forbids me but honesty compels me.”

    ==> “Modesty forbids me but honesty compels me.”

  • Sean

    Thanks for catching the typo; I’ll fix it.

  • Pingback: Texas bound « blueollie()

  • David Moles

    I rather like, from the same paper:

    But there is no reason for the cosmological constant (equivalently, the absolute energy density of the vacuum) to vanish. Indeed, if it were not for the irrefutable empirical evidence, one would expect it to be a typical microphysical number, [and] the radius of the universe to be less than a kilometer.

  • Michele Tizzoni

    I’m so sad to hear this! When I read his “Aspects of Symmetry” I thought it was the best physics book ever written. We’ll miss you Sidney.

  • Haelfix

    A wonderful man. Everytime I encountered him I was awed by his modesty and wit.

    A great loss for physics, he was a giant of the field.

  • marc

    Perhaps my favorite Coleman quote was “QCD is the first theory to go from hypothesis to dogma without going through the intermediate stage of verification”.

    He was extraordinarily generous with his time. I recall calling him once, out of the blue, and asking him whether the tunnelling rate for vacuum decay was gauge-dependent (since the effective potential is). He spent the next half hour on the phone with me (then a lowly postdoc) constructing a proof that the decay rate is gauge-independent.

    He has taught a generation of physicists, and we’ll all miss him.

  • Scott Dodelson

    I echo the sentiments, especially about his generosity, of those who posted above. I applied to the Harvard theory group as a grad student and got a rejection letter from Sidney Coleman with the quote “I hope you will consider us again should the opportunity arise.” The phrase was so elegant, especially given the circumstances, that it stuck with me. Many years later, I was running the selection process for postdocs at Fermilab and inserted that phrase into my response whenever I had to let someone know we were making an offer to someone else. It probably didn’t make them feel any better but it always reminded me of our [physicists’] collective heritage.

    My favorite story was the time he was asked to teach a course at 10AM. He said he had to refuse because he couldn’t stay up that late.

  • Mark Srednicki

    When I was a grad student at Stanford, Sidney spent a sabbatical at SLAC. At one of the regular Friday lunch seminars (to be given by someone else), Sidney walked in wearing an outrageous green velvet suit. As all eyes turned to him, he looked around the room, and said “I’m sorry; I thought this was to be a formal seminar.”

    (Later he admitted that he was attending some other formal function later that day.)

  • Josh

  • Pingback: Steve’s No Direction Home Page » Blog Archive » Coleman on Quantum Flapdoodle()

  • Chanda

    I have wonderful memories of waiting for the discussion section for classical mechanics right down the hall from Sidney Coleman’s office. He would walk by, a little bent over, still wearing his bicycle helmet and ankle reflectors. We’d look at him, then look at the bust of Einstein and think … is it possible? Looking back, what was striking about Professor Coleman wasn’t so much his passing (literally passing!) resemblance to Einstein, but the apparent humility of this little old man who, at an advanced age, still rode his bicycle to Jefferson Lab to pursue the mysteries to which he had devoted his life.

    That’s an image which has always stayed with me and which I think about often. It is a reminder of the glory of the process, that though we may not get all the answers in the end, several decades decades down the line, we can still be inspired to go into the office and wonder about how it all works. That is a tremendous gift.

  • Mark Srednicki

    The Chicago Tribune has an obituary today:

  • roberta gordon

    I have written an obituary of Sidney for the Harvard Gazette, which can be read at:

    Roberta Gordon


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Cosmic Variance

Random samplings from a universe of ideas.

About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] .


See More

Collapse bottom bar