My Life as a Quant (5 page)

Also at Columbia, but not yet Nobelists at that time, were Leon Lederman, Jack Steinberger, and Mel Schwartz, all of them renowned even then for a host of elegant experiments and discoveries. In 1988 they received their Nobel Prize for having shown, almost thirty years earlier, that there were not one, but two different types of the neutrino that Fermi had proposed. (The discovery of a third type of neutrino in 2000 was less astonishing and definitely not Nobel-worthy.)

Finally, fiercely brightest among all the stars in the Columbia firmament was Tsung-Dao Lee, the embodiment and perhaps even the cause of all the good and bad qualities of the department. He had won his Nobel Prize in 1957, at the age of 31, for theoretical investigations that led to the startling discovery of the so-called nonconservation of parity. Lee and his fellow Prize-winner C. N. Yang had intrepidly suggested that nature's laws were not symmetric with respect to the seemingly arbitrary human definitions of “left” and “right.” It was an almost unbelievable hypothesis, but they proposed experiments to test it. In less than a year they were proved correct. When I arrived at Columbia only eight years later, the consequences of this discovery were still working their way through the framework of physics.

“T. D.,” as everyone called him, was Pupin's version of the Pope and the Last Emperor of China rolled into one. He was a holy terror, self-centered and intense. About ten years ago I saw a photograph of him in the literary magazine
Grand Street
, taken as part of a series of photographs of scientists writing on blackboards. One was of Feynman, lively and jovial, lecturing on QED. Another featured Mitchell Feigenbaum of the Rockefeller University, examining his doubling equations that revealed the hidden order behind apparently chaotic phenomena. Most of the physicists looked prosaic, even Gell-Mann himself. But T. D.'s photo was different. Taken in the 1950s, it showed his fervent young face glowing with light as he spoke, for all the world looking like Moses descending from Sinai. T. D. set the tone at Columbia. His presence could inspire, but it could consume, too.

The faculty were not the only extraordinary beings at Columbia. Many of the students seemed to be
wunderkinder
, too. My graduate classes, even the advanced ones, always contained a smattering of precocious smart-aleck American undergraduates. I was envious and wary of them. Some, sporting crewcuts and narrow-shouldered dark suits with ties, were relics of the Fifties; others had lank, long, hair and dressed in faded jeans and sweatshirts. But whatever they wore, they all raised their hands in class to ask questions whose answers they already knew.

I was awed by these people who knew more than they had been taught. In South Africa I had mastered only a limited number of skills really well, and that knowledge lasted a lifetime. There, I had waited obediently year after year to get to the level at which “they” would begin to teach “me” the things I was able to handle. It had never occurred to me that I could learn what I wanted when I chose. In America, I was alarmed to see students who set about learning things on their own. I'm still embarrassed to admit to myself that I almost never studied anything I wasn't officially taught. I recall one major exception. In my fourth year of college I spent many months studying unified field theories of gravitation and electromagnetism for my honors' thesis. My independent investigation of the extension of Einstein's theory of gravitation exhilarated me, but this autonomy was an exception.

In 1966 and during subsequent years, I dreamed ambitious dreams about success on the scale of T. D. Lee. By this unrealistic measure, few of the
wunderkinder
fulfilled the full magnitude of their intimidating promise. One became a think-tank military analyst whom I was pleased to recognize on television during the Gulf War following the Iraqi invasion of Kuwait. Another completed a PhD in physics, moved to medical school, began a residency in psychiatry, and finally became a well-known neural-net theorist. A third, after winning the prize for the best physics undergraduate at Columbia, struggled with manic depression. Determined to keep studying, he would keep a running daily log on his canary-yellow legal notepad of the exact number of minutes he had spent actually working at full concentration. Each time he paused or took a break, he stopped the clock and he wrote down the number of minutes he had worked since the last interruption. At the end of the day he computed the total. Compulsive myself, I was sympathetic to his counting; I knew how few were the hours in the day one actually works seriously and undistractedly, and was momentarily tempted to start my own time sheet.

I learned one lesson from the fates of both the professors and students I met at Columbia: In the end, character and chance counted at least as much as talent. Luck, combined with what my mother called
sitzfleisch
, the capacity to persevere, played an overwhelming role.

First in Cape Town and then in New York, I had been steadily learning what kind of physics suited me.

Like most physicists, I was a reductionist: I believed that you can explain complex things by reducing them to their constituents. Biology depends on chemistry; chemistry is merely the physics of molecules and atoms; atoms are made out of electrons and nuclei; nuclei contain protons and neutrons, and protons and neutrons seem to be made of quarks. What are the ultimate subnuclear particles at the putative root of this hierarchy, and what are the laws that determine their behavior? These questions are the domain of particle physics.

Particle physicists are snobs who think that their field is the source of the most fundamental knowledge, and take some mischievous pleasure in denigrating other messier or more complex areas of physics. Gell-Mann, the codiscoverer of the Eightfold Way and the discoverer of quarks, succinctly summarized the latent prejudice of most particle physicists about the superiority of their enterprise when he famously referred to solid state physics, the apparently more mundane study of bulk matter and its variety of forms, as “squalid state physics.”

Nowadays, not everyone agrees with Gell-Mann's clever
bon mot
. Over the last twenty years physicists have discovered a deep commonality between large-scale bulk matter and small-scale particle physics. Much of what is new and interesting in both fields seems to emerge from what is called their “many-body” nature: Both bulk matter and tiny particles can each be viewed as resembling a medium, each made out of a very large number of similar constituents. When many similar constituents are clumped together, their collective behavior can display completely new and unexpected characteristics. A drop of water can suddenly freeze and turn solid in a way that no single water molecule can. A ripple of excitement or a hush of expectation can sweep over a crowd but not over a single individual. In the words of another Nobel Prize-Winner, P.W. Anderson, “More is Different!” He, and many other “squalid-state” physicists believe that there is no single grand reductionist Theory of Everything.

It is unlikely one will ever know who is right, but, like most aspiring physicists of the postwar period, I was immensely attracted by the reductionist point of view. I wanted to be the ultimate reductionist, a particle physicist.

Technically, I still had to choose between being a theorist or an experimentalist, but for me, this wasn't much of a choice. The essence of theoretical physics is the attempt to look at the universe, and then mentally apprehend its structure. If you are right, you emulate Newton and Einstein: You find one of the Ten Commandments. You write down a simple set of laws that, plucked from nowhere, miraculously describes and predicts how God's world works. This was the struggle to which I aspired. Anything else would have been a compromise that I was not prepared to make.

Even within theoretical particle physics there are further refinements. Pure theory is the search for abstract laws, for a formulation of the divine commandments that rule the world. But, for every Moses descending from the mountain with a valid new law, there are countless well-intentioned prophets whose proposed laws turn out to be wrong. So how does one tell when a theory is right?

Beauty, even mathematical beauty, is not enough. Physicists must test a new theory by elaborating the ways in which it manifests itself in the world. Physicists who do so-called phenomenology work out the detailed and observable consequences of a theory, providing the practical link between principles and experiment, between mind and matter. Phenomenologists elaborate the theory; they create heuristic approximations to engineer the theory into a pragmatic tool; they propose experiments to validate or refute a theory, using the theory itself to compute the expected results. Phenomenologists deal a little more with the ripples on the surface and a little less with the laws beneath it.

Though I wanted to do pure theory, I ultimately ended up spending much of my life in physics as a phenomenologist. Over the long run, this stood me in very good stead. When I moved to Wall Street, I found quantitative finance to resemble phenomenology much more than it resembled pure theory. Quantitative finance is concerned with the techniques that people use to value financial contracts and, given the fluctuations of the human psyche, it is a pragmatic study of surfaces rather than a principled study of depths. Physics, in contrast, is concerned with God's canons, which seem to be more easily captured in the simple broad statements that characterize profound physical laws.

I had a passion for the content of physics, but I was also possessed by a hungry ambition for its earthly rewards. Both passion and hunger persisted over the years, despite the inevitable disappointments. Ten years later, as a postdoctoral researcher at Oxford in 1976, I experienced a minor epiphany about ambition's degradation. At age 16 or 17, I had wanted to be another Einstein; at 21, I would have been happy to be another Feynman; at 24, a future T. D. Lee would have sufficed. By 1976, sharing an office with other postdoctoral researchers at Oxford, I realized that I had reached the point where I merely envied the postdoc in the office next door because he had been invited to give a seminar in France. In much the same way, by a process options theorists call time decay, financial stock options lose their potential as they approach their own expiration.

1
The dermatologist's poorly concentrating nephew was Jonathan Dorfan. A few years later he, too, came to graduate school in the United States, where he is now head of the Stanford Linear Accelerator Center, one of the few great global laboratories for experimental particle physics.

2
You may think me pedantic to list the actual course number. But even now, more than thirty years later, each prosaic course number still conjures up a vivid subworld of a certain year, a particular classroom, a specific professor, a sliding chalkboard, and a noisily clanking steam radiator, together with the exciting sensation of being on the threshold of mastering some new and arcane alchemical subject.

3
During my last few years at Goldman, Sachs, I interviewed undergraduates applying for jobs in investment banking, and I was often surprised at how little of their coursework some of them recalled, how little a sense they had of the essence of their field. I met juniors majoring in statistics who couldn't define standard deviation and students who had taken several courses in electromagnetic theory but couldn't remember Maxwell's equations. What I had learned I had learned well. Theirs sometimes seemed a wasted education.

Life as a graduate student

Wonderful lectures

T. D. Lee, the brightest star in the firmament

Seven lean years

Getting out of graduate school only half-alive

If you didn't mind wasting the best years of your youth, graduate student life at Columbia was paradise. Once you got over the first two hurdles—passing the PhD qualifying exams and obtaining a research advisor—no one seemed to give a damn about what happened to you. Being a graduate student was not a bad sinecure. The university just kept funneling you a small but livable stipend and hoped you stayed out of their way. I spent seven biblically-lean years in the physics department. One friend spent ten. We both got out alive.

Some didn't. It wasn't long before we had all heard the legend about the graduate student who had shot his PhD advisor. Several years ago I read a
New York Times
article about two graduate students who committed suicide while studying in the Harvard laboratory of Nobel Prize-winner Professor E. J. Corey. In a subsequent letter to the Sunday
New York Times
magazine of December 20, 1998, Linda Logdberg of Upper Nyack, New York, wrote in to comment on life as graduate student:

. . . Perhaps even more now than then, graduate education is an extended adolescence during which highly intelligent young people see their world shrink to fit the dimensions of their advisor's laboratory. . . . With their identities bound to the outcome of the thesis project, graduate students are socialized to view other options (teaching, industry, even changing to another type of work altogether) with contempt. Wanting a decent wage and meaningful work that occupies, say, only 50 hours per week are considered signs of selling out.

It's an accurate description. We went into science for the love of it and thought nothing else was half as good. Some failed the PhD qualifying exam and left at the end of one year. Others passed the exam and then gave up before getting a thesis advisor. Many threw in the towel mid-thesis. The remainder struggled through and went on to a life of itinerant postdoctoral research. Few of us had an easy time. Ms. Logdberg is especially accurate in acknowledging the undeclared self-hatred we felt in looking down on those of our friends who, like failed novitiates in a nunnery, shamefacedly transferred their efforts to less ambitious endeavors. “Shame is Pride's cloke,” I read in Blake's
Proverbs of Hell
;I understood exactly what he meant. But that was later.