ECG Sudarshan, physicist who proposed faster than light theory, dies at 86

A brilliant physicist and a scintillating man is how N. Mukunda, 79, a retired professor from Indian Institute of Sciences (IISc), remembers his former teacher and long-time collaborator, Ennackal Chandy George Sudarshan. The acclaimed Indian theoretical physicist died on Monday, aged 86.

Sudarshan was India’s best known theoretical physicist, who was professor emeritus at University of Texas at Austin in the United States at the time of his death.

“He was a scintillating person filled with ideas,” Mukunda says of his former doctoral advisor. Urjit Yajnik, a professor of physics at IIT Bombay, who was supervised by Sudarshan in the 1980s, remembers him as a father-figure who was “difficult to work with because he was a man of strong opinions”.

Sudarshan was born in Kottayam, Kerala in 1931. He studied at CMS College in his hometown before attending the University of Madras and later the Tata Institute of Fundamental Research. He later studied and taught at the University of Rochester and then at the University of Texas at Austin, where he taught for over 40 years.

The best time to catch up with Sudarshan, according to Yajnik, was on his home turf in Texas. Yajnik remembers driving up to his supervisor’s house to find him in his comfortable veshti (dhoti ), listening to Carnatic music, busy gardening. “These were free-for-all sessions,” Yajnik recalls, “we could tell him anything, disagree with him on anything.”

What charmed both students was not just Sudarshan’s brilliance as a physicist but his wit, a combination that made him “unusual” . Despite the controversy about not receiving a Nobel for his substantial contributions to his field overshadowing his later years, the renowned physicist never lost his good humour.

Sudarshan was born in Kottayam, Kerala in 1931. He studied at CMS College in his hometown before attending the University of Madras and later the Tata Institute of Fundamental Research. He later studied and taught at the University of Rochester and then at the University of Texas at Austin, where he taught for over 40 years.

Yajnik remembers a man who was caught between India and the US.

Though Sudarshan left India to pursue his own doctoral studies at the University of Rochester under Robert Eugene Marshak in 1955, he never lost touch with India, visiting a few times every year, according to Mukunda. Sudarshan set up the Centre for Theoretical Studies at the IISc in Bangalore in 1972. Initially a place of multidisciplinary studies, it soon gave rise to three specialized centres: Centre High Energy Physics, the Centre for Atmospheric and Oceanic Sciences and the Centre for Ecological Sciences.

The weak interaction in elementary particles based on research that Sudarshan did in 1957 is one of his two contributions that Mukunda believes are most important. “Sudarshan and Robert Marshak made crucial step in this long story lasting from 1934 to 1967-68, when a final understanding on the question emerged,” Mukunda said. In 1979, three scientists who brought the line of development to its conclusion were awarded the Nobel: Sheldon Lee Glashow, Abdus Salam and Steven Weinberg.

“Everybody knew of their contribution, nobody denies it,” Mukunda said of the scientific community. But wider renown and prestige that comes with the Nobel eluded Sudarshan his entire life.

His later work in quantum optics done around 1963 was another notable contribution seminal in many ways, Mukunda said. It became the basis for the Glauber–Sudarshan P representation. However, only Roy J. Glauber was awarded the Nobel in 2005 “for his contribution to the quantum theory of optical coherence.”

In 2007, speaking to the Hindustan Times, Sudarshan said: “The 2005 Nobel prize for Physics was awarded for my work, but I wasn’t the one to get it. Each one of the discoveries that this Nobel was given for work based on my research.”

Sudarshan was deeply disappointed at being passed over. “He believed he was not judged and treated fairly,” Mukunda said. But he was also a man who “was never at a loss for words.”

In 2007, speaking to the Hindustan Times he said: “The 2005 Nobel prize for Physics was awarded for my work, but I wasn’t the one to get it. Each one of the discoveries that this Nobel was given for work based on my research.”

He was honoured with several other prestigious awards like ICTP Dirac Medal, Padma Vibhushan (2007), Padma Bhushan, Majorana Prize, TWAS Prize, Bose Award (1977) and C V Raman Award (1970).

The disappointment over the Nobel didn’t dim the eminent physicist’s sense of humour.

At a social dinner in Bangalore with many non-scientist celebrities, Sudarshan recounted to Mukunda with amusement how he was mistaken for an actual Nobel prize winner. Someone across the table pointed to him and asked a neighbour: “Who is that bearded person there?” The reply: “Don’t you know? He is the world famous physicist Chandrasekhar from the University of Chicago who won the Nobel Prize for his work on liquid crystals!” Despite overhearing the conversation, Sudarshan did not correct the mistake.

MAJOR CONTRIBUTIONS:

1) Quantum theory for tachyons: Particles that could possibly move faster than light, which challenged Einstein’s assertion that nothing with mass can travel faster than the speed of light. The theory was never fully developed.

2) V-A theory of the weak force: A theory about weak interaction between subatomic particles. This weak nuclear force fundamentally preferred one handedness over the other.

3) Glauber–Sudarshan P representation: A quantum mechanical description of photons to explain the quantum properties of light