Thursday, October 07, 2010

Luis Alvarez quotes

Someone posted the first quote below as a comment and I thought I'd share it, as well as some others. Alvarez was one of the greatest experimentalists of all time. He and Shockley both missed the Terman cut by a few points, which just goes to show you what a noisy predictor any test administered to kids is.

The world of mathematics and theoretical physics is hierarchical. That was my first exposure to it. There's a limit beyond which one cannot progress. The differences between the limiting abilities of those on successively higher steps of the pyramid are enormous. I have not seen described anywhere the shock a talented man experiences when he finds, late in his academic life, that there are others enormously more talented than he. I have personally seen more tears shed by grown men and women over this discovery than I would have believed possible. Most of those men and women shift to fields where they can compete on more equal terms.

[I still shed the occasional tear today! Trivia question: what was Larry Summers' major when he entered MIT?]

My observations of the young physicists who seem to be most like me and the friends I describe in this book tell me that they feel as we would if we had been chained to those same oars. Our young counterparts aren't going into nuclear or particle physics (they tell me it's too unattractive); they are going into condensed-matter physics, low-temperature physics, or astrophysics, where important work can still be done in teams smaller than ten and where everyone can feel that he has made an important contribution to the success of the experiment that every other member of the collaboration is aware of. Most of us do physics because it's fun and because we gain a certain respect in the eyes of those who know what we've done. Both of those rewards seem to me to be missing in the huge collaborations that now infest the world of particle physics.

Most of us who become experimental physicists do so for two reasons; we love the tools of physics because to us they have intrinsic beauty, and we dream of finding new secrets of nature as important and as exciting as those uncovered by our scientific heroes. But we walk a narrow path with pitfalls on either side. If we spend all our time developing equipment, we risk the appellation of 'plumber', and if we merely use the tools developed by others, we risk the censure of our peers for being parasitic.

With modern weapons-grade uranium, the background neutron rate is so low that terrorists, if they had such material, would have a good chance of setting off a high-yield explosion simply by dropping one half of the material onto the other half. Most people seem unaware that if separated U-235 is at hand, it's a trivial job to set off a nuclear explosion, whereas if only plutonium is available, making it explode is the most difficult technical job I know.

Dirac politely refused Robert's [Robert Oppenheimer] two proffered books: reading books, the Cambridge theoretician announced gravely, 'interfered with thought'.

Here is a review of Alvarez's memoir Alvarez: Adventures of a Physicist, by the professor who first taught me quantum mechanics in 1982-3:

Luis Alvarez was likely the best American experimental physicist of the 20th century. ...

He invented radar for instrument flight landing, discovered new elements, invented new accelerators, invented clever optical devices, built the big bubble chambers of particle physics, x-rayed the pyramid at Giza with cosmic rays, used elementary physics to conclusively solve all the unknowns of the Kennedy assassination in Dallas in 1963, looked in Moon rocks for magnetic monopoles, and hypothesized the cause of the disappearance of the dinosaurs 65 million years ago.

He was an observer on the plane that dropped the first nuclear bomb on Japan, kept a few Moon rocks on the mantle in his living room where he hosted weekly gatherings of students and physicists, and "did physics" until he died of esophogeal cancer.

This book is a joy for a physicist to read, but anyone who is curious about what physicists really do and how they approach problems both large and small, this book is a treasure.

1 comment:

tc said...

There's no inherent reason why people capable of top-level math and physics, the most "abstract" and high-level of subjects, should tend to be people with high g (i.e. good on average at a variety of tests). It seems to be true, which is a second nontrivial empirical fact. Certainly the top guys were dedicated to their fields their whole lives. But there are many famous first-rank people in other fields who freely admit they "dropped out" of physics because they knew they weren't good enough to be among the best. The reverse is not true.

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