Ennackal Chandy George Sudarshan (also known
as E. C. G. Sudarshan; 16 September 1931 – 14
May 2018) was an Indian theoretical physicist
and a professor at the University of Texas.
Sudarshan has been credited with numerous
contributions to the field of theoretical
Physics including optical coherence, Sudarshan-Glauber
representation, V-A theory, Tachyons, Quantum
Zeno effect, open quantum system and Lindblad
equation, spin–statistics theorem, non-invariance
groups, positive maps of density matrices,
quantum computation among others. His contributions
include also relations between east and west,
philosophy and religion.
== Early life ==
George Sudarshan was born in Pallam, Travancore.
Despite being raised in a Syrian Christian
family, he later left the religion in large
part due to marrying Lalitha, a Hindu fellow
student. They were married from 1954 to 1990
and have three sons, Alexander, Arvind (deceased)
and Ashok. He considers himself a "Vedantin
Hindu". He mentions disagreements with the
Church's view on God and lack of spiritual
experience as reasons why he left Christianity.He
studied at CMS College Kottayam, 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 Homi Bhabha as well as others. Subsequently,
he moved to University of Rochester in New
York to work under 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
Julian Schwinger as a postdoctoral fellow.
== Career ==
Sudarshan has 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. He also developed a
quantum representation of coherent light later
known as Sudarshan–Glauber representation
(for which controversially Glauber was awarded
the 2005 Nobel prize in Physics ignoring Sudarshan's
contributions).
Sudarshan's most significant work might be
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
the first to propose the existence of tachyons,
particles that travel faster than light. He
developed formalism called dynamical maps
that is one of the most fundamental formalism
to study the theory of open quantum system.
He, in collaboration with Baidyanath Misra,
also proposed the quantum Zeno effect.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.He has taught at
the Tata Institute of Fundamental Research
(TIFR), University of Rochester, Syracuse
University, and Harvard. From 1969 onwards,
he has been 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 on 16th
Sept, 2011. His areas of interest include
elementary particle physics, quantum optics,
quantum information, quantum field theory,
gauge field theories, classical mechanics
and foundations of physics. He is also deeply
interested in Vedanta, on which he lectures
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 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. "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 Sudarshan–Glauber representation."
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 Sudarshan–Glauber representation)
in quantum optics, for which Roy J. Glauber
won his share of the prize. Sudarshan and
others physicists sent a letter to the Nobel
Committee claiming that the P representation
had more contributions of "Sudarshan" than
"Glauber". 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.In
2007, 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."
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?"
== Awards ==
Kerala Sastra Puraskaram for lifetime accomplishments
in science, 2013
Dirac Medal of the ICTP, 2010
Padma Vibhushan, second highest civilian award
from the Government of India, 2007
Majorana Prize, 2006
First Prize in Physics, 1985
TWAS Prize, 1985
Bose Medal, 1977
Padma Bhushan, third highest civilian award
from the Government of India, 1976
C V Raman Award, 1970
== Bibliography ==
Doubt and Certainty with Tony Rothman
Classical Dynamics with N. Mukunda
Fundamentals of Quantum Optics with John R.
Klauder
Introduction to Elementary Particle Physics
with Robert Marshak
From Classical to Quantum Mechanics: An Introduction
to the Formalism, Foundations and Applications
with Giampiero Esposito and Giuseppe Marmo
Pauli and the Spin-Statistics Theorem with
Ian Duck and Wolfgang Pauli
== 
See also ==
Winners of Padma Bhushan
== Notes
