(Who shared Nobel Prize for Physics in 1979)
by (Dr) Surjit Singh Bhatti
Formerly, Professor & Head, Department of Physics,
Dean, Sciences, Guru Nanak Dev University,
Born on 29th of January 1926 in Jhang, now in Pakistan, Salam became one of the youngest persons to be elected a Fellow of the Royal Society (FRS) in 1959. He shared the 1979 Nobel Prize in Physics (with Sheldon Glashow and Steven Weinberg), for his contributions to the Electroweak Unification Theory. This theory gave important information about sub-atomic Elementary Particles of matter and predicted the existence of a novel Weak Neutral Current that explained many complex mysteries of nature. Its predictions have been confirmed experimentally at the European Center for Nuclear Research (CERN), in Geneva. He was the first-ever Pakistani to receive a Nobel Prize in Physics, and the only Nobel Laureate from that country until Malala Yousufzai won the Nobel Peace Prize in 2014.
Dr Abdus Salam was Advisor to Pakistan’s Ministry of Science and Technology, Founder-Director of Space and Upper Atmosphere Research Commission and Chief of the country’s International Atomic Energy Commission. In 1998, the Government of Pakistan issued a commemorative stamp to recognize his services. Salam founded the Third World Academy of Sciences (TWAS) and helped in the creation of a number of International Centers for Scientific Research. The International Center for Theoretical Physics (ICTP) at Trieste, in Italy, was established by him in 1964. This was renamed after Abdus Salam in 1997.
In 1954, Salam joined St John’s College as a Professor of Mathematics. In 1957, he was invited by the Imperial College, where he set up the Department of Theoretical Physics. In 1957, Punjab University conferred upon him an Honorary Doctorate for his contributions in Particle Physics. At Cambridge, he formed a strong group of Researchers in Theoretical Physics. Salam took a Fellowship at the Princeton University in 1959, where he met with Robert Oppenheimer and to whom he presented his research work on neutrinos (the neutral, mass-less sub-atomic particles). They discussed the important problems in electrodynamics and their solution.
Background of Electroweak Unification Theory
There are four main physical forces in nature: Gravitational attraction, Electromagnetic forces between charged particles (which may be attractive or repulsive), and the short-range Strong nuclear (attractive) and Weak nuclear interactions. The Strong nuclear forces keep the heavy particles: protons and neutrons together in the atomic nuclei. The Weak interactions cause radioactive decay of the (neutral) neutron into a (positive) proton, with the emission of a light (negative) electron and the (neutral) mass-less neutrino. Energy is produced in the Sun when its hydrogen nuclei fuse together to give helium, caused by the Weak Interactions. Had this force been stronger, the Sun would have been too short-lived for the evolution of life on the Earth. This Weak Interaction is called beta-decay.
Glashow, Salam and Weinberg developed a theory, called Electroweak Unification Theory, which unifies the Weak and Electromagnetic Interactions in a mathematical formalism. Their theory is fundamental to the existing “Standard Model”, which describes how elementary particles of matter interact through the three different forces: Electromagnetic, Strong, and the Weak interactions. It also predicts the existence of a new type of interaction, in which the particles do not change their charges, as in Electromagnetic Interactions, via a weak neutral current. This is different from beta-decay of the neutron, where the charges change when the neutron is changed into a proton.
The CERN Experiment at Geneva
In this experiment, some atomic nuclei were bombarded with beams of neutrinos. The results were interpreted in terms of effects of weak neutral current on the usual electromagnetic photons, which produced a new type of photons (called weak vector bosons). These differ from the usual mass-less photons by having a large mass, corresponding to the short range of the Weak Interaction. The Electroweak Unification Theory had already laid down the basis of the discovery of these photons (by Higgs). These massive photons, now known as Higgs bosons, move in an Energy Field (called the Higgs Field) that transmits mass to bodies travelling through it. This is how stars and other bodies in the universe are believed to have acquired huge masses. Using the concept of the Higgs bosons, this theory helps to predict the existence of proton decay.
Helping Science in Developing Countries
Salam was the man behind Pakistan’s first National Space Agency. He recalled eminent physicists, who had left the country (specially for Switzerland to join CERN), back to Pakistan to help establish numerous Scientific Research Centers. He advised them to guide and supervise research activities in their academic institutions. Salam expanded research in all Sciences and new Technologies in Pakistan and in the other developing countries by sending more than 500 young scientists to USA, UK, and the ICTP, for advanced studies, research, and training.
On the direction of Salam, plutonium and uranium exploration was carried out in the country. In 1961, Salam signed an agreement with USA for developing Space Science, as a result of which NASA built a Space Facility (a Flight Test Range) in Baluchistan, with Abdus Salam as its first Technical Director. In 1964, Abdus Salam was made head of the country’s International Atomic Energy Agency (IAEA) delegation and represented Pakistan for a decade. At IAEA, he stressed the importance of Nuclear Power plants. As a result, the country signed co-operation deal with Canada to set up a Nuclear Power plant near Karachi. In 1965, the US provided a small Research Reactor and helped in the establishment of Pakistan Institute of Nuclear Science and Technology at Islamabad. Both Nuclear Energy and Advanced Space Technology research and development in Pakistan were established by Abdus Salam and grew due to his dedicated and relentless efforts.
Awards and Recognition
In 1959, Dr Abdus Salam got Star of Pakistan and in 1979, he was given Nishan-e-Imtiaz awards by the President of Pakistan, for his outstanding services to the country. The National Center for Physics (NCP) houses the Abdus Salam Museum, depicting his life and work. In addition to the Nobel Prize, Knighthood of the British Empire (KBE) and Fellowship of Royal Society (FRS), some of the other awards conferred on Salam include the following.
Hopkins Prize (Cambridge University) for “the most outstanding contribution to Physics in 1957-1958”, Adams Prize (Cambridge University) in 1958, Pride of Performance Award by Pakistan (1958), First Maxwell Medal (Physical Society, London) in 1961, Hughes Medal (Royal Society, 1964), Atoms for Peace Award (1968), Robert Oppenheimer Memorial Medal (University of Miami, 1971), Matteuci Medal (Accademia Nazionale dei Lincei, Rome) in 1978, John Torrence Tate Medal (American Institute of Physics) in 1978, Einstein Medal (UNESCO, Paris) in 1979, Birla Award (Indian Physics Association) in 1979, Gold Medal (Czechoslovak Academy of Sciences, Prague) in 1981, Lomonosov Gold Medal (USSR Academy of Sciences) in 1983, First Edinburgh Medal (Scotland) in 1988, “Genoa” International Development Prize (Italy) in 1988 and the Copley Medal (Royal Society, London) in 1990.
“Abdus Salam Medal”, is presented by the Third World Academy of Sciences in his memory, since 1995 to persons who have served the cause of Science in the Developing World. Another award, “Abdus Salam Shield of Honor in Mathematics” was initiated by the National Mathematical Society of Pakistan to promote and recognize quality research in Mathematics, since 2016. Several Institutes have been named after Dr Abdus Salam in Pakistan and elsewhere to honor him and inspire the younger generations. Dr Abdus Salam expired on the 21st of November 1996 in Oxford (UK).
Every year, two “Abdus Salam Science Fairs” are held, one in Canada and the other in the USA. Each is organized as a nation-wide event for young scientists in an effort to motivate the youth toward scientific endeavors. A road was named after Dr Abdus Salam in Geneva to honor him, after his theoretical predictions were confirmed at CERN and in some other laboratories in the world.
PS. The author visited ICTP, Trieste, Italy, to attend a month-long Course on the Physics of High Temperature Super Conductors (HTSC) in October 1990.