A Scholar with Physical Ambitions
By Katherine Yungmee Kim
When Clifford Johnson talks about the formation of crystals, he refers
to its “beautiful math.” He reminisces about an earlier “flirtation”
with theoretical condensed matter physics. But his real passion ignites
when he is discussing his current research: string theory, matrix
models, D-branes and black holes.
Johnson, a professor in the College’s physics department, came to USC
College in the fall of 2003 as part of the Senior Faculty Hiring
Initiative. This advancement effort strives to hire outstanding senior
faculty and well-established associate professor candidates.
“Cliff is a leading expert on the most recent developments in the
theory of superstrings … and a skilled lecturer,” says Gene Bickers,
chair of the department of physics and astronomy.
Johnson has been studying string theory since the late 1980s. String
theory is a revolutionary field in contemporary physics as it attempts
to unify gravity, electromagnetism, the strong nuclear force and the
weak nuclear force—the four forces of nature—within a single
mathematical framework.
Born in London and raised for ten years on the Caribbean island of
Montserrat, Johnson “always wanted to be a scientist.” He decided when
he was nine that he would specialize as a physicist (he looked it up in
the dictionary) and claims that he’s been “boringly single-minded” ever
since.
He got his bachelors in physics from Imperial College at London
University, and went straight on to obtain his Ph.D. at Southampton
University. In graduate school, he worked with a small group doing
cutting edge work in Conformal Field Theory and in a formulation of
string theory called Matrix Models.
Up until 1989, studies of string theory were largely perturbative,
meaning the strings were interacting weakly, if at all. Matrix Models
were very exciting at the time because they gave the tools to
understand non-perturbative string theory. “We would really like to
understand when strings are interacting with each other strongly,”
Johnson explains, “because we’re trying to understand how black holes
work and how Hawking radiation works … how the universe itself works.”
(Hawking radiation is the idea that black holes glow when a particle
from a virtual particle pair escapes after its anti-particle is
absorbed).
But Johnson found himself outdated at The Institute for Advanced Study
at Princeton—“the Mecca of Physics.” By the time he arrived there to do
his first postdoc, Matrix Models had lost their allure; it was thought
that the aspects of physics they produced were inconsistent. Despite
the fact that Johnson and his colleagues in Southampton showed that the
models’ non-perturbative physics were fully consistent, with a
definition as natural as the mainstream models’, the rest of the
physics world wasn’t listening. “It gave quite wonderful physics but it
was never used for anything and it’s remained always at the back of my
mind,” says Johnson.
This fall his ideas were vindicated when the Princeton physics
establishment wrote a paper, connecting Johnson’s thesis work on Matrix
Models from 12 years ago to many modern ideas in string theory. He has
since written a follow-up paper. “It’s all of a sudden become
relevant,” he says.
At Princeton, he studied string theory under renowned physicist Ed
Witten. He also found his physics voice working with Joe Polchinski at
the Institute for Theoretical Physics at UC Santa Barbara. There, he
became widely recognized for his work on D-branes—higher
dimensional membrane-like structures.
His eloquence found a purpose in teaching. Johnson started lecturing at
Princeton, and later became an assistant professor at the University of
Kentucky and a professor at the University of Durham in England.
Fundamental Science in Africa
His enthusiasm for teaching parallels his intellectual appetite.
Johnson referred to his childhood in the Caribbean, as a time when he
was always running into a “limit to what you could find in the
library.” Likewise while lecturing in South Africa, he was struck by
the pervasive post-apartheid problems in education, where he felt
students were simply missing opportunities. So he developed a
scientific education program called ASTI—The African Summer Theory
Institute—for students, high school teachers and researchers to convene
and discuss scientific ideas.
This pilot program in Cape Town, sponsored in 2004 by the Flora Family
Foundation, the Perimeter Institute of Theoretical Physics and the
South African National Astrophysics and Space Science program, will
allow aspiring African scientists to explore topics in science. Through
lectures, master classes and colloquia, it will expand their knowledge
of resources and career prospects.
It is the first forum for such groups to meet together in the same place.
In early 2004 Johnson plans to oversee the inaugural ASTI program. In
the spring, he will teach an undergraduate physics course on “what
everyone encounters everyday.” Boiling water as thermodynamics, turning
on a light switch as electromagnetism—he has seen that a lot of people
want to know how such simple phenomena work. “And it’s great,” he says
happily, “to be the first person to tell them that.”
|
|
|
