Abdus Salam

[This article was published in Physics Today (August 1997). It is being

reproduced here with the permission of the author]



Abdus Salam died at age 70 on 21 November 1996, at his home in Oxford,

England. He was best known for his pioneering work on electroweak

unification, for which he shared the Nobel Prize in Physics in 1979

with Sheldon Glashow and Steven Weinberg. Salam will be remembered

also for his invaluable contributions to the propogation of science in

the third world. He founded the International Center for Theoretical

Physics (ICTP) in Trieste, Italy, and directed it for over 30 years;

he also helped create other international research centers, several

international foundations, such as the Third World Academy of Science,

and a number of international prizes.



Salam was born in Jhang, a district in the part of British India, that

is now Pakistan. Known at an early age for his sharp intellect, he

completed his undergraduate education at the University of the Punjab

in 1946, and won a scholarship to continue his graduate studies at the

University of Cambridge's St. John's College. He excelled there,

securing a first (top honors) in both physics and mathematics. While

seeking a research problem for his thesis, he asked the advice of Paul

Matthews, who was about to finish his PhD. Mathews had been attempting

to extend to meson theories, which describe the nuclear forces, the

renormalization techniques that had recently been applied so

successfully to avoid the infinities in quantum

electrodynamics. Matthews challenged Salam to solve the problem of the

so-called overlapping divergences, which arise in meson theories in higher

orders of perturbation theory. To Matthews's great surprise, Salam

arrived at a complete solution to the problem in a few months. This

thesis made Salam very well known at the beginning of his career.



After finishing his PhD at Cambridge in 1951, Salam returned to

Pakistan as a professor of mathematics at the University of the

Punjab, hoping to build research groups in theoretical physics in his

own country. However, he was frustrated in achieving his goals by both

the lack of official support and the acute isolation in physics that

he faced in Pakistan. He felt that he could serve his country better

by staying abroad, so he returned to Cambridge in 1954 as a lecturer

and fellow of St. John's College. Three years later, he accepted a

professorship at what is now the University of London's Imperial

College of Science, Technology and Medicine, where he succeeded in

establishing one of the best theoretical physics groups in the world,

well known for its contributions to the role of symmetries in particle

physics. He maintained his professorship at Imperial College to the

end of his career, despite spending most of his time after 1964 at the

ICTP.



From 1957 to 1967, Salam, initially in collaboration with John Ward,

attempted to unify the radioactive weak and electromagnetic forces -an

idea introduced by Julian Schwinger in 1957. Following a suggestion by

Glashow on the usefulness of the gauge symmetry SU(2)xU(1) and a

crucial observation made by Peter Higgs and independently by

F. Englert and R. Brout and (earlier) by Philip Anderson on how

massless gauge particles can acquire masses through spontaneous

breaking of symmetries, Weinberg (in 1967), and, independently Salam

(in 1968) proposed a model for electroweak unification based on the

idea of a spontaneously broken SU(2)xU(1) gauge symmetry.



During 1974 and 1975, Salam collaborated with John Strathdee on the

superspace-superfield formalism for dealing with a new type of

symmetry - supersymmetry. The

Salam-Strathdee formalism has turned out to be an indispensable tool

for dealing with the quantum behavior of supersymmetric field

theories.



My personal collaboration with Salam started in the summer of 1972 and

remained intense for over ten years. Together, we introduced the idea

of an underlying unity of quarks and leptons and, simultaneously, of

gauge forces.



In 1973, despite the skepticism of the physics community at the time,

Salam and I noted that a gauge unification of quarks and leptons would

inevitably lead to non-conservation of baryon and lepton numbers and

thereby naturally to an unstable proton. These ideas have matured and

evolved considerably. Salam had hoped to see a more final chapter of

this story of unification in his lifetime. We were both encouraged,

however, to see that the search for proton decay was continuing with

the recent completion of the Superkamiokande detector in Japan.



During our collaboration, Salam always reacted to our occasional

disagreements with a good-natured spirit. If he were greatly excited

about an idea that I did not like, he would impatiently ask, "My dear

sir, what do you want? Blood?" I would reply, "No, Professor Salam. I

would like something better." Whether I was right or wrong, he never

took it ill.



While Salam was moving forward in his research, he never lost sight of

his ardent desire to help the growth of science and technology in the

third world. Determined to help, he approached the International

Atomic Energy Agency (IAEA) of the United Nations in 1960 for support

of what was to become the ICTP. Salam's proposal met with great

resistance, with one delegate from a developed nation saying,

"Theoretical physics is the Rolls-Royce of sciences - the developing

countries need only bullock carts." After Salam and several colleagues

lobbied intensely for four years, Salam finally succeeded in creating

the center in 1964, with the partial support from the IAEA (now taken

over by UNESCO) and primary support from the government of Italy.



Thanks to Salam's tireless efforts, the ICTP has emerged as one of the

finest research-cum-training institutions in the world, not only

producing high quality science but also providing opportunities for

scientists from the developing and developed nations to interact

regularly through annual workshops and summer schools. In its 33

years, the ICTP has hosted some 60,000 visits by experimental and

theoretical research physicists, about half of them are from the

developing countries.



Salam dreamed of creating 20 international centers like the ICTP,

spread throughout the world and emphasizing different areas of science

and technology. He appealed vigorously to the developed as well as the

developing countries and to the World Bank for funds to create the

centers. Meanwhile Salam also dreamed of creating a "World

University", which would be funded internationally and would be linked

for its functioning to a consortium of universities worldwide.



Salam's efforts in these directions in the last eight years of his

life were unfortunately severely hampered by a crippling neurological

illness, attributed to a variant of Parkinson's disease. Thanks to his

own initiative and that of several others, he nevertheless succeeded

in creating the International Center for Genetic Engineering and

Biotechnology, with components in Trieste and Delhi, and the

International Center for Science and High Technology in Trieste.



Salam will surely be remembered as one of the great scientists of the

20th century and as a humanitarian who devoted much of his life to

uplifting the status of science and technology in the third

world. Salam may have been somewhat ahead of his time in dreaming of

20 international centers and a world university. It remains for the

present generation of scientists and world leaders to fulfill this

dream.