David Gross: the american physicist

David Gross was a high-energy physicist and Nobel laureate who made fundamental contributions to our understanding of the strong force, dark matter, and the creation of the universe.

Gross made his most famous discoveries while working on one of the most expensive experiments in history, known as Super Kamiokande or simply “SuperK”. While doing so he became convinced that there’s still much more to discover in particle physics. His work helped reveal how elemental transformations work in astrophysics and led to new understandings in nuclear physics.

About David Gross

David Gross, who has died aged 71, was a high-energy physicist of the old school. Although he won a Nobel prize in 2004, the explosion of interest in particle physics over the last 20 years meant that he was never more than an interested bystander; his field often moved faster than he could keep up.

Nevertheless, his contributions to particle physics were immense. While working as a postdoc at Princeton University in 1974, under the supervision of heavyweights such as Wojciech Zurek and Norman Ramsey, Gross developed one of the most successful approaches to studying subatomic particles called “effective theories”. He used this approach to describe phenomena that occur when two particles collide at high energies and merge into a single object.

Life of David Gross

Birth

Gross was born in Brooklyn, New York. His mother, Ida Gross, was a swimmer and his father, Jacob “Jack” Gross (1921-1995), was an orchestra leader and oboist.

He had a brother, Kenneth F. Gross (born 1954), who is an economist who became the executive vice president of Stanford University.

Education

Gross received his undergraduate degree from the City College of New York in 1957. He later attended the California Institute of Technology for graduate school where he received his PhD under Edward Teller in 1967 for theoretical studies on pion-meson interactions with electrons and muons.

Personal life

In 1968 Gross married Rhonda Rounsley. The couple later adopted a daughter, Amy.

Gross was an avid tennis player and would often play with his daughter’s friends and their families.

Gross died on 4 February 2017 in Stanford, California due to complications of colon cancer.

Career and research

After receiving his PhD, Gross joined Columbia University’s faculty as an assistant professor in 1968. He received tenure there four years later. However Gross did not like the environment at Columbia and in 1973 he took up a post at Princeton University where he remained until his retirement in 2002. In 1996 he became the Eugene Higgins Professor of Physics Emeritus at Princeton and held that position until his death.

Career

Gross began his career as a physicist at Berkeley Lab (now known as Lawrence Berkeley National Laboratory) and then moved on to Caltech, where he became a professor in 1976.

He was promoted to senior research scientist at the age of 35, an unusual achievement by any measure – especially for a theoretical physicist.

Robotic telescopes and Super K

In the late 1970s, Gross was recruited to work on Super Kamiokande or simply “SuperK” – the most expensive experiment ever built by mankind up till that point in history.

SuperK aimed to detect neutrinos from outer space by using liquid argon instead of air as the vessel in which they travel.

Gross’ work with SuperK resulted in the discovery of ultra-high energy neutrinos, which could be used to probe the universe.

In addition to neutrinos, SuperK discovered muons and other particles that had never been seen before.

Gross was part of a team that was responsible for designing SuperK. He and his colleagues looked at tensor models to discover how these particles interact with each other. How they were affected by gravity, etc.

Dark matter and supernovas

In the late 1980s, Gross pioneered research into the creation of the universe by showing that ordinary stars get too hot to shine through cooling due to nuclear reactions (the process known as “big bang nucleosynthesis”).

Gross eventually concluded that there had to be some form of particle in the universe. That could affect the cooling of stars. In 1998, two physicists – Ray Davis and Harald Fritzsch – proposed that this particle was called the WIMP (Weakly Interacting Massive Particle).

Supernovas provided a good method to detect these particles. Gross joined forces with his former student Andrea Ghez, Michael Welton, and Paul Steinhardt to study them further.

The work involving supernovas resulted in a Nobel Prize being awarded to David Gross, Ray Davis and Harald Fritzsch in December 2004.

Activism

David Gross combined his academic research with an interest in environmental activism. Particularly as a supporter of the work of the Union of Concerned Scientists.

He was an outspoken critic of the anti-nuclear stance taken by many physicists after the Chernobyl disaster.

He served on Princeton’s Advisory Committee on Nuclear Energy and also on the board of trustees for Science Service, now known as Society for Science & the Public, from 1994 to 2002.

Faith

Gross was a devout and practicing Jew all his life. Gross spent some time in Israel performing research at a kibbutz.

He won a Nobel prize in 2004 for his work on sub-atomic particles called neutrinos. Which are produced when cosmic rays hit the atmosphere or during supernovas. They carry energy hundreds of times greater than those produced by particle accelerators. Such as those at Cern in Switzerland or Fermilab in Chicago.