As every schoolchild knows, everything is made up from atoms. Every atomic nucleus is made up from quarks – the smallest ‘building block’ there is. What acts as the cement, binding the blocks together, is the ‘strong force’, also known as the ‘colour force’, which acts between the quarks inside the proton and the neutron. However, unlike conventional forces such as magnetism or gravity, where the effects are stronger the closer together the objects are, the strong force works more like a rubber band, stronger – as if stretched – when the quarks are apart, but relaxed when the quarks are in close proximity. Then the force is so weak that they behave almost as free particles. This phenomenon is called ‘asymptotic freedom’.
It was for this discovery that Gross, working with Frank Wilczek, and David Politzer, working independently, were awarded the Nobel Prize in Physics, 30 years after the theory was published in 1973 in a mathematical framework that came to be known as Quantum ChromoDynamics, QCD. This was an important contribution to the Standard Model, the theory that describes all physics connected with the electromagnetic force (which acts between charged particles), the weak nuclear force (which acts in radioactive decay) and the strong force.
David Jonathan Gross was born in Washington, DC, in 1941, the eldest of four sons and the grandson of Jewish immigrants from Czechoslovakia-Hungary, and David’s fi rst ‘job’, at the age of 11, was to proofread his father’s book, The Legislative Struggle: A Study in Social Combat. His father helped write the US Employment Act of 1946 and accompanied the first US diplomatic/aid packages to Israel in 1953. His mother was born in the Ukraine, moving to the US after WWI, and was a chemistry graduate. The Grosses remained in Israel and David became an avid reader and student, interested in physics and mathematics, soon exceeding the knowledge of his teachers. He gained a BSc at the Hebrew University and went on to take his physics doctorate from the University of California at Berkeley.
In 1966 he was nominated to the Harvard Society of Fellows and in 1969 he joined the Princeton faculty as an assistant professor and stayed for 27 years. His students there included his fellow laureate Frank Wilczek. After the discovery of asymptotic freedom, Gross continued to work on QCD but in the early 1980s, he began to work on string theory and in 1984 discovered the heterotic string, which it was hoped might explain the Standard Model – unifying all the forces of nature and confronting quantum gravity. In 1996 he accepted the directorship of the Institute for Theoretical Physics in Santa Barbara. He has two children by his fi rst wife, Shulamith Toaff and a stepdaughter with his second wife, Jacquelyn Savani.
This text and the picture of the Nobel Laureate were taken from the book: "NOBELS. Nobel Laureates photographed by Peter Badge" (WILEY-VCH, 2008).
Picture: © Peter Badge/ Foundation Lindau Nobelprizewinners Meetings at Lake Constance |