George Sudarshan
E. C. G. Sudarshan at TIFR Mumbai in 2009
Born(1931-09-16)16 September 1931
Died13 May 2018(2018-05-13) (aged 86)[1]
Alma materCMS College Kottayam
Madras Christian College
University of Madras
University of Rochester
Known forCoherent states
Optical equivalence theorem
Glauber–Sudarshan representation
GKSL equation
V-A theory
Quantum Zeno effect
Open quantum system
Spin–statistics theorem
Lalita Rau
(m. 1954⁠–⁠1990)
Bhamathi Gopalakrishnan
(m. 1990)
  • Ipe Chandy[2] (father)
  • Achamma[2] (mother)
Scientific career
FieldsTheoretical physics
InstitutionsUniversity of Texas at Austin
Indian Institute of Science
Institute of Mathematical Sciences, Chennai
Harvard University
University of Rochester
Tata Institute of Fundamental Research
Doctoral advisorRobert Marshak
Doctoral studentsMohammad Aslam Khan Khalil
Narasimhaiengar Mukunda

Ennackal Chandy George Sudarshan (also known as E. C. G. Sudarshan; 16 September 1931 – 13 May 2018)[2][3] was an Indian American[4] theoretical physicist and a professor at the University of Texas. Prof.Sudarshan has been credited with numerous contributions to the field of theoretical physics, including Glauber–Sudarshan P representation, V-A theory, tachyons, quantum Zeno effect, open quantum system and quantum master equations, spin–statistics theorem, non-invariance groups, positive maps of density matrices, and quantum computation.

Early life

Ennackal Chandy George Sudarshan was born in Pallom, Kottayam, Travancore, British India. He was raised in a Syrian Christian family, but later left the religion and converted to Hinduism following his marriage.[5]: 243[5]: 243[5]: 250 He married Lalita Rau on December 20, 1954, and they have three sons, Alexander, Arvind (deceased) and Ashok.[6] George and Lalita were divorced in 1990 and he married Bhamathi Gopalakrishnan in Austin, Texas.[6]

He studied at CMS College Kottayam,[7] and graduated with honors from the Madras Christian College in 1951. He obtained his master's degree at the University of Madras in 1952. He moved to Tata Institute of Fundamental Research (TIFR) and worked there for a brief period with Dr. Homi Bhabha as well as others. Subsequently, he moved to University of Rochester in New York to work under Prof.Robert Marshak as a graduate student. In 1958, he received his Ph.D. degree from the University of Rochester. At this point he moved to Harvard University to join Prof. Julian Schwinger as a postdoctoral fellow.


Dr. Sudarshan made significant contributions to several areas of physics. He was the originator (with Robert Marshak) of the V-A theory of the weak force (later propagated by Richard Feynman and Murray Gell-Mann), which eventually paved the way for the electroweak theory. Feynman acknowledged Sudarshan's contribution in 1963 stating that the V-A theory was discovered by Sudarshan and Marshak and publicized by Gell-Mann and himself.[8] He also developed a quantum representation of coherent light later known as Glauber–Sudarshan representation (for which controversially Glauber was awarded the 2005 Nobel prize in Physics ignoring Sudarshan's contributions).

George Sudarshan and Steven Weinberg at Austin.
George Sudarshan and Steven Weinberg at Austin.

Sudarshan's most significant work may have been his contribution to the field of quantum optics. His theorem proves the equivalence of classical wave optics to quantum optics. The theorem makes use of the Sudarshan representation. This representation also predicts optical effects that are purely quantum, and cannot be explained classically. Sudarshan was also advocate for the existence of tachyons, particles that travel faster than light.[9] He developed a fundamental formalism called dynamical maps to study the theory of open quantum system. He, in collaboration with Baidyanath Misra, also proposed the quantum Zeno effect.[10]

Sudarshan and collaborators initiated the "Quantum theory of charged-particle beam optics", by working out the focusing action of a magnetic quadrupole using the Dirac equation.[11][12]

He taught at the Tata Institute of Fundamental Research (TIFR), University of Rochester, Syracuse University,[13] and Harvard. From 1969 onwards, he was a professor of physics at the University of Texas at Austin and a senior professor at the Indian Institute of Science. He worked as the director of the Institute of Mathematical Sciences (IMSc), Chennai, India, for five years during the 1980s dividing his time between India and USA. During his tenure, he transformed it into a centre of excellence. He also met and held many discussions with philosopher J. Krishnamurti. He was felicitated on his 80th birthday, at IMSc Chennai[14] on 16 September 2011. His areas of interest included elementary particle physics, quantum optics, quantum information, quantum field theory, gauge field theories, classical mechanics and foundations of physics. He was also deeply interested in Vedanta, on which he lectured frequently.

Controversy regarding Nobel Prize

Sudarshan began working on quantum optics at the University of Rochester in 1960. Two years later, Glauber criticized the use of classical electromagnetic theory in explaining optical fields, which surprised Sudarshan because he believed the theory provided accurate explanations. Sudarshan subsequently wrote a paper expressing his ideas[15] and sent a preprint to Glauber. Glauber informed Sudarshan of similar results and asked to be acknowledged in the latter's paper, while criticizing Sudarshan in his own paper.[16] "Glauber criticized Sudarshan’s representation, but his own was unable to generate any of the typical quantum optics phenomena, hence he introduces what he calls a P-representation, which was Sudarshan’s representation by another name", wrote a physicist. "This representation, which had at first been scorned by Glauber, later becomes known as the Glauber–Sudarshan representation."[17]

Sudarshan was passed over for the Physics Nobel Prize on more than one occasion, leading to controversy in 2005 when several physicists wrote to the Swedish Academy, protesting that Sudarshan should have been awarded a share of the Prize for the Sudarshan diagonal representation (also known as Glauber–Sudarshan representation) in quantum optics, for which Roy J. Glauber won his share of the prize.[18] Sudarshan and other physicists sent a letter to the Nobel Committee claiming that the P representation had more contributions of "Sudarshan" than "Glauber".[19] The letter goes on to say that Glauber criticized Sudarshan's theory—before renaming it the "P representation" and incorporating it into his own work. In an unpublished letter to The New York Times, Sudarshan calls the "Glauber–Sudarshan representation" a misnomer, adding that "literally all subsequent theoretic developments in the field of Quantum Optics make use of" Sudarshan's work— essentially, asserting that he had developed the breakthrough.[20][21]

In 2007, Prof.Sudarshan told the Hindustan Times, "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."[22] Sudarshan also commented on not being selected for the 1979 Nobel, "Steven Weinberg, Sheldon Glashow and Abdus Salam built on work I had done as a 26-year-old student. If you give a prize for a building, shouldn’t the fellow who built the first floor be given the prize before those who built the second floor?"[22]



See also


  1. ^ "Ennackal Chandy George Sudarshan September 16, 1931 - May 13, 2018". Beck Funeral Home. 15 May 2018. Retrieved 17 May 2018.
  2. ^ a b c Bhamathi, Gopalakrishnan (2021). "George Sudarshan: Perspectives and Legacy". Quanta. 10: 75–104. doi:10.12743/quanta.v10i1.174. S2CID 245482293.
  3. ^ "Acclaimed scientist ECG Sudarshan passes away in Texas". Mathrubhumi. 14 May 2018. Retrieved 21 December 2018.
  4. ^ Luis J. Boya, Laudatio for E. C. G. SUDARSHAN On his 75th BirthDay. Jaca, (HU), Spain, September 18, 2006, Journal of Physics: Conference Series 87 (2007) 012001 doi:10.1088/1742-6596/87/1/012001
  5. ^ a b c Clayton, Philip (2002). "George Sudarshan". In Richardson, W. Mark; Russell, Robert John; Clayton, Philip; Wegter-McNelly, Kirk (eds.). Science and the Spiritual Quest: New Essays by Leading Scientists. London: Routledge. ISBN 9780415257664.
  6. ^ a b "Ennackal Chandy George Sudarshan (September 16, 1931 – May 13, 2018)". Austin, Texas: University of Texas. 2021. Retrieved 24 December 2021.
  7. ^ "A proud moment for CMS College: Prof. Sudarshan delights all at his alma mater". The Hindu. 5 July 2008. Archived from the original on 2 August 2008. Retrieved 5 April 2010.
  8. ^ The beat of a different drum: The life and science of Richard Feynman by J. Mehra Clarendon Press Oxford (1994), p. 477, and references 29 and 40 therein
  9. ^ Time Machines: Time Travel in Physics, Metaphysics, and Science Fiction, p. 346, by Paul J. Nahin
  10. ^ Sudarshan, E. C. G.; Misra, B. (1977). "The Zeno's paradox in quantum theory" (PDF). Journal of Mathematical Physics. 18 (4): 756–763. Bibcode:1977JMP....18..756M. doi:10.1063/1.523304. OSTI 7342282.
  11. ^ R. Jagannathan, R. Simon, E. C. G. Sudarshan and N. Mukunda, Quantum theory of magnetic electron lenses based on the Dirac equation, Physics Letters A, 134, 457–464 (1989).
  12. ^ R. Jagannathan and S. A. Khan, Quantum theory of the optics of charged particles, Advances in Imaging and Electron Physics, Editors: Peter W. Hawkes, B. Kazan and T. Mulvey, (Academic Press, Logo, San Diego, 1996), Vol. 97, 257–358 (1996).
  13. ^ Catterall, Simon; Hubisz, Jay; Balachandran, Aiyalam; Schechter, Joe (5 January 2013). "Elementary Particle Physics at Syracuse. Final Report". Syracuse University: 14. doi:10.2172/1095082. OSTI 1095082. Retrieved 26 February 2021. ((cite journal)): Cite journal requires |journal= (help)
  14. ^ "Sudarshan Fest" (PDF). 16 September 2011.
  15. ^ Sudarshan, Ennackal Chandy George (1963). "Equivalence of semiclassical and quantum mechanical descriptions of statistical light beams". Physical Review Letters. 10 (7): 277–279. Bibcode:1963PhRvL..10..277S. doi:10.1103/PhysRevLett.10.277.
  16. ^ "Physicist Sudarshan's omission questioned". The Hindu. 2 December 2005.[dead link]
  17. ^ "ECG Sudarshan, physicist who proposed faster than light theory, dies at 86". 14 May 2018. Retrieved 20 December 2018.
  18. ^ Zhou, Lulu (6 December 2005). "Scientists Question Nobel". The Harvard Crimson. Archived from the original on 4 February 2012. Retrieved 22 February 2008.
  19. ^ Epstein, David (7 December 2005). "Nobel Doubts". Inside Higher Ed. Retrieved 26 February 2021.
  20. ^ "UT Austin Mourns Passing of George Sudarshan, Titan of 20th Century Physics". 20 December 2018. Retrieved 20 December 2018.
  21. ^ "First Runner-up". 20 December 2018. Archived from the original on 4 March 2016. Retrieved 20 December 2018.((cite web)): CS1 maint: unfit URL (link)
  22. ^ a b Mehta, Neha (4 April 2007). "Physicist cries foul over Nobel miss". Hindustan Times. Archived from the original on 20 March 2008. Retrieved 22 February 2008.
  23. ^ "KU to confer honorary doctorates on Narlikar, Kris Gopalakrishnan". The Hindu. 21 August 2019. Retrieved 5 November 2020.
  24. ^ Balasubramanya, M. K.; Srinivas, M. D. (2019). "Ennackal Chandy George Sudarshan". Physics Today. 72 (4): 63. Bibcode:2019PhT....72d..63B. doi:10.1063/pt.3.4190. Retrieved 20 October 2023.
  25. ^ "Padma Awards" (PDF). Ministry of Home Affairs, Government of India. 2015. Archived from the original (PDF) on 15 October 2015. Retrieved 21 July 2015.