George Sudarshan | |
|---|---|
 E. C. G. Sudarshan at TIFR Mumbai in 2009 | |
| Born | (1931-09-16)16 September 1931 |
| Died | 13 May 2018(2018-05-13) (aged 86)[1] Austin, Texas, United States |
| Alma mater | CMS College Kottayam Madras Christian College University of Madras University of Rochester |
| Known for | Coherent states Optical equivalence theorem Glauber–Sudarshan representation GKSL equation V-A theory Tachyon Quantum Zeno effect Open quantum system Spin–statistics theorem |
| Spouses | |
| Children | 3 |
| Parents | |
| Awards |
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| Scientific career | |
| Fields | Theoretical physics |
| Institutions | University of Texas at Austin Syracuse University Indian Institute of Science Institute of Mathematical Sciences, Chennai Harvard University University of Rochester Tata Institute of Fundamental Research |
| Doctoral advisor | Robert Marshak |
| Doctoral students | Mohammad Aslam Khan Khalil Narasimhaiengar Mukunda |
Ennackal Chandy George Sudarshan (also known asE. C. G. Sudarshan; 16 September 1931 – 13 May 2018)[2][3] was anIndian American[4] theoreticalphysicist and a professor at theUniversity of Texas. Sudarshan has been credited with numerous contributions to the field of theoretical physics, includingGlauber–Sudarshan P representation,V-A theory,tachyons,quantum Zeno effect,open quantum system andquantum master equations,spin–statistics theorem, non-invariance groups, positive maps of density matrices, and quantum computation.
Ennackal Chandy George Sudarshan was born inPallom,Kottayam,Travancore,British India. He was raised in aSyrian Christian family, but later left the religion and converted toHinduism following his marriage.[5]: 243 [5]: 243 [5]: 250 He married Lalita Rau on 20 December 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 atCMS College Kottayam,[7] and graduated with honors from theMadras Christian College in 1951. Sudarshan obtained hismaster's degree at theUniversity of Madras in 1952. He moved toTata Institute of Fundamental Research (TIFR) and worked there for a brief period with Dr.Homi Bhabha as well as others. Subsequently, he moved toUniversity of Rochester inNew York to work under Prof.Robert Marshak as a graduate student. In 1958, he received hisPh.D. degree from the University of Rochester. At this point he moved toHarvard University to join Prof.Julian Schwinger as a postdoctoral fellow.
Sudarshan made significant contributions to several areas of physics. He was the originator (withRobert Marshak) of the V-A theory of theweak force (later propagated byRichard Feynman andMurray 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 aquantum representation ofcoherent light later known asGlauber–Sudarshan representation (for which controversially Glauber was awarded the 2005 Nobel prize in Physics ignoring Sudarshan's contributions).
Sudarshan's most significant work may have been his contribution to the field ofquantum 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 an advocate for the existence oftachyons, particles that travel faster than light.[9] He developed a fundamental formalism called dynamical maps to study the theory ofopen quantum system. He, in collaboration with Baidyanath Misra, also proposed thequantum 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 theDirac equation.[11][12]
He taught at theTata 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 theIndian Institute of Science. He worked as the director of theInstitute 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 philosopherJ. Krishnamurti. He was felicitated on his 80th birthday, at IMSc Chennai[14] on 16 September 2011. His areas of interest includedelementary particle physics,quantum optics,quantum information,quantum field theory,gauge field theories,classical mechanics and foundations of physics. He was also deeply interested inVedanta, on which he lectured frequently.[citation needed]
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 theGlauber–Sudarshan representation."[17]
Sudarshan was passed over for the Physics Nobel Prize on more than one occasion, leading tocontroversy 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 whichRoy 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 toThe 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, Sudarshan told theHindustan 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 andAbdus 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]
