11/06/2001 08:00:00

Physicist Awarded Prize for Development of Superstring Theory

PASADENA, Calif.—A theoretical physicist's research lab consists of little more than a chalkboard and chalk, a world of knotty mathematical equations that seek to explain why our physical world is the way it is.

For his pioneering work in the development of one such possible explanation, known as superstring theory, John Schwarz, the Harold Brown Professor of Theoretical Physics at the California Institute of Technology, has been awarded the 2002 Dannie Heineman Prize for Mathematical Physics. The prize is awarded annually by the American Physical Society and the American Institute of Physics for, "valuable published contributions made in the field of mathematical physics." Schwarz is sharing the award with Dr. Michael B. Green of the University of Cambridge.

String theory evolved in the 1970s in an attempt to provide one all-encompassing framework that would explain the nature of nature—everything from the macro level of the cosmos to the micro level of subatomic particles (particles hundreds of times smaller than the nucleus of an atom). Further, it incorporated all the forces of nature (such as gravity) that affect the basic structure of the world.

With string theory, physicists take a different view of the fundamental units of matter. When combined, these smallest building blocks create all the physical things we see. Instead of viewing them as infinitesimally tiny points in space, though, string theorists view them as tiny, one-dimensional, stringlike bits of matter that vibrate. They are not ordinary strings, but they behave in ways that can be described mathematically, by equations that also account for two other physical laws of nature, relativity and quantum mechanics. (In a similar vein, mathematicians can write equations to describe the patterns of vibration that produce different notes from the string of a guitar; thus the term "string theory.") Each pattern of vibration of the string corresponds to a different particle of matter.

But by the late 1970s interest in string theory had faded after a number of predictions it made conflicted with the results of experiments. Most physicists therefore abandoned the theory.

But not Schwarz, Green, and a handful of others. Schwarz, for one, stuck to his guns, saying at the time that "the mathematical structure of string theory was so beautiful and had so many miraculous properties that it had to be pointing toward something deep."

In 1984, Schwarz and Green published a landmark paper that was based on more than 12 years of research. In it, they found a way to resolve these conflicts, by suggesting, among other things, that more dimensions may exist in our world then the three—height, width, and depth—we are familiar with.

Instead, they suggested a mathematical theory that included 10 dimensions. It's a world we can't experience, but that mathematically makes sense. How can we think of our world as having extra dimensions? As one physicist explained it, imagine that you can move only in two dimensions, length and width, in a big room. But the third dimension, height, isn't large like the other two but instead is curled up at each point of matter in a tiny circle, so that you don't experience it. Presumably, the additional dimensions suggested by Schwarz and Green are so small, existing at the subatomic level, that we can't experience them. However, the properties of these extra dimensions are expected to have other consequences that can be observed.

Schwarz termed this new theory superstring theory, because it incorporates a special kind of symmetry called supersymmetry. Symmetry, which is very common and important in physics, concerns the fact that equations (and sometimes nature) look the same when observed in different ways. For example, a sphere looks the same after it is rotated. Supersymmetry, which is one of the spin-offs of string theory, is a less intuitive and more quantum mechanical kind of symmetry. Their research reignited string theory, which today remains one of the hottest areas in theoretical physics. It is also the leading candidate for the elusive "theory of everything" that physicists seek. It is for this work that Schwarz and Green have been awarded the Heineman Prize.

Schwarz has worked on superstring theory for most of his professional career. In 1986 he became a Fellow of the American Physical Society. In 1987 he received a prestigious MacArthur Fellowship, and in 1997 he was elected to the National Academy of Sciences. The Dannie Heineman prize was established in 1959 to encourage further research in the field of mathematical physics. As a recipient, Schwarz joins a number of esteemed physicists, including Caltech's Murray Gell-Mann (1959) and the likes of Freeman Dyson (1965), Roger Penrose (1971), and Stephen Hawking (1977). The prize was established by the Heineman Foundation for Research, Educational, Charitable, and Scientific Purposes, Inc., and is administered jointly by the American Physical Society (APS) and the American Institute of Physics.

The prize will be awarded at the April 2002 APS meeting to be held in Albuquerque, New Mexico.