University of Minnesota
School of Physics & Astronomy

Abigail and John Van Vleck Lectures

David Gross Biography

David Jonathan Gross was born in Washington, D.C., on February 19, 1941. He received his undergraduate degree from Hebrew University in Jerusalem in 1962 and then returned to the United States to continue his education at the University of California, Berkeley. From that latter institution he received his Ph.D. in physics in 1966. He left Berkeley later that year to serve as a junior fellow at Harvard University.

Gross began his professional teaching career at Princeton University in 1969 and was appointed professor of physics in 1972. During that same period, between 1970 and 1975, he also became a fellow at the Sloan Foundation. Gross remained at Princeton until 1996, where he was named Eugene Higgins Professor of Physics, 1986-95, and Thomas Jones Professor of Mathematical Physics, 1995-7. In 1997 he was named director of the Institute of Theoretical Physics at the University of California, Santa Barbara, a position he holds until this day. In 2002 he was named the Frederick W, Gluck Chair in Theoretical Physics, an endowed chair for the director of the Kavli Institute for Theoretical Physics. Gross's impact on the field of particle physics was first felt in the early 1970s when, as a young professor, he and his fellow Nobel laureate Frank Wilczek, made a number of remarkable discoveries concerning quarks. Quarks are the theoretical constituents of the neutrons and protons that make up the nucleus which are thought to come in pairs. Unlike neutrons and protons, however, quarks have never been seen apart from one another. As early as the 1930s physicists have attempted to unlock the secrets of atomic nuclei, often with little success. Researchers knew that neither gravity not electromagnetism (two of nature's four elemental forces, which also include the "strong force" of the nuclei and the "weak force" which causes radioactive decay), were strong enough to keep nuclei together or shape them in any way. By the late 1960s, primarily through the work of Dr. Murray Gell-Mann and Dr. George Zweig, physicists had discovered that neutrons and protons seemed to be made of quarks. But quarks were behaving in a very unusual manner. As quarks were never seen in isolation, it seemed that powerful forces were binding them together. However, through experimentation conducted in particle accelerators, researchers noted that quarks inside protons, as viewed at short distances, appeared to be behaving as free particles, almost as if no force was being exerted on them at all. The idea staggered the scientific community--how could the quarks be moving about freely and yet still not have the ability to get out?

In 1973 two papers, one by Gross and Wilczek, the other by H. David Politzer, published in the scientific journal Physical Review Letters, sought to answer this question. At the time Gross was a young Associate professor at Princeton, Wilczek his first graduate student. Politzer, working on the problem separately at Harvard University, was also a graduate student at the time. Using pencil and paper each of the three men mathematically deduced that the bonds holding quarks together actually strengthened as the particles drew further away from one another. It was as if the particles were connected by a rubber band, which pulls objects more tightly together the more it is stretched. As Gross, Wilczek, and Politzer explained it, while the pull of gravity and electromagnetism decreases with distance as objects move farther away from one another, the particles that carry the strong force between quarks, called gluons, increases the further apart they move. The researchers dubbed this phenomenon "asymptotic freedom."

The general theory, laid out in their seminal papers, is known as quantum chromodynamics (QCD), and now serves as the underlying basis for the theory of the strong force---Quantum Chromodynamics In the New York Times (October 6, 2004), Dennis Overbye presented a succinct overview of QCD: "In the modern version of this theory, quarks come in six types--fancifully named up, down, strange, charmed, top and bottom--and three 'colors,' named red, green and blue. The colors are like electrical charges that interact by exchanging bundles of energy called gluons, just as electrical charges attract or repel by exchanging photons." These gluons, have a color change when they interact with one another. This process is called chromodynamics. As the particles transmitting the strong force, the gluons are unique in nature; not only do they interact with quarks, but also with each other. This explains therefore how quarks, when coming in closer contact to one another, have a weaker attraction, unlike a force like gravity which is strengthened when objects are brought in closer proximity.

Quantum chromodynamics has also contributed greatly to the Standard Model, which details how the three basic forces of particle physics--the electromagnetic force, the weak force, and the strong force--interact. With the aid of QCD, physicists are now able to explain how the strong force of the nucleus acts between the quarks inside the proton and neutron. In addition, QCD has helped to bring the scientific community closer to formulating a unified theory, which would add the fourth force, gravity, to the Standard Model and explain all the workings of the universe through the same theory. On October 5, 2004 the Royal Swedish Academy of Sciences announced that the 2004 Nobel Prize in Physics would be given in three equal parts to Gross, Wilczek, and Politzer "for the discovery of asymptotic freedom in the theory of the strong interaction." The press release went on to note: "Thanks to their discovery, David Gross, David Politzer and Frank Wilczek have brought physics one step closer to fulfilling a grand dream, to formulate a unified theory comprising gravity as well-a theory for everything."

He has made seminal contributions to the theory of Superstrings, where he took a critically inventive role in the explosive development of string theory in the 1980s, a burgeoning enterprise that brings gravity into the quantum framework. With collaborators he originated the "Heterotic String Theory," the prime candidate for a unified theory of all the forces of nature. He continues to do research in this field at the KITP, a world center of string theory.

In addition to receiving the Nobel Prize in Physics, David J. Gross has received numerous award for his work, including the J. J. Sakurai Prize of the National Academy of Sciences in 1986, a MacArthur Foundation Fellowship in 1987, the Dirac Medal in 1988, the Oscar Klein Medal from Stockholm University in 2000, and the Harvey Prize of the Technion in 2000, European Physical Society Prize in Elementary Particle Physics, 2003, the Grande Medaille D'Or of the French Academy of Science in 2004, as well honorary degrees from Hebrew University, Israel in 2001, Montpellier University, France in 2002, Sao Paulo University, Brazil in 2006.

He has been a fellow of the American Physical Society since 1974, a fellow of the American Academy of Arts and Sciences since 1985, a member of the National Academy of Sciences since 1986, a fellow of the American Association for the Advancement of Science since 1987, a Fellow of Indian Academy of Science, Bangalore, India, elected 2007, and Member of the American Philosophical Society, elected 2007. David J. Gross has been married to Jacquelyn Savani since 2001. He has two children, Ariela and Elisheva. -- C. M.