Cumrun Vafa
Born	1960 Tehran, Iran
Nationality	Iranian-American
Fields	Physics
Institutions	Harvard University
Alma mater	MIT, Princeton University
Doctoral advisor	Edward Witten
Notable awards	Dirac Medal, Eisenbud Prize

Cumrun Vafa (Persian: کامران وفا‎, pronounced [kɔːmˈrɔːn væˈfɔː]; born 1960 in Tehran, Iran) is an Iranian-American leading string theorist from Harvard University where he started as a Harvard Junior Fellow. He is a recipient of the 2008 Dirac Medal.

Birth and education[link]

Cumrun Vafa was born in Tehran, Iran in 1960. He graduated from Alborz High School and went to the US in 1977. He got his undergraduate degree from Massachusetts Institute of Technology with a double major in physics and mathematics. He received his Ph.D. from Princeton University in 1985 under the supervision of Edward Witten.^[1] He then became a junior fellow at Harvard, where he later got a junior faculty position. In 1989 he was offered a senior faculty position, and he has been there ever since. Currently, he is the Donner Professor of Science at Harvard University.^[2]

Research[link]

Cumrun Vafa is a string theorist. His research is focused on the nature of quantum gravity and the relation between geometry and quantum field theories. He is known in the string theory community for his co-discovery, with Strominger, that the Bekenstein-Hawking entropy of a black hole can be accounted for by solitonic states of superstring theory, and for expounding the relation between geometry and field theories that arise through string dualities (culminating in the Gopakumar-Vafa conjecture). This topic has been known as "geometric engineering of quantum field theories". In 1997, he developed F-theory.

He is also interested in understanding the underlying meaning of string dualities, as well as trying to apply superstring theory to some unsolved questions of elementary particle physics such as the hierarchy problem and the cosmological constant problem.

He has published numerous articles on topological string theories, and has written a paper with Andy Strominger about the microscopic origin of black hole entropy.

He is also a trustee of Network of Iranians for Knowledge and Innovation (NIKI).

See also[link]

• Vafa-Witten theorem

References[link]

External links[link]

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Joe Polchinski in Santa Barbara

Joseph Polchinski (born on May 16, 1954 in White Plains, New York) is a physicist working on string theory. He graduated from Canyon del Oro High School in Tucson, Arizona in 1971, obtained his B.S. degree from Caltech in 1975, and his Ph.D. from the University of California, Berkeley in 1980 under the supervision of Stanley Mandelstam. After postdoctoral positions at SLAC (1980–82) and Harvard (1982–84) he was a professor at the University of Texas at Austin from 1984 to 1992. Since 1992 he has been a professor at the University of California, Santa Barbara and a permanent member of the Kavli Institute for Theoretical Physics in Santa Barbara.

Polchinski is the author of the two volume textbook, String Theory, published in 1998. Among his contributions to theoretical physics, D-branes are the best known. In 2008 he won the Dirac Medal for his work in superstring theory.

Polchinski's paradox[link]

In 1990, commenting on the Novikov self-consistency principle (in relation to sending objects or people through a traversable wormhole into the past, and the time paradoxes that could result), Polchinski raised a potentially paradoxical situation involving a billiard ball sent through a wormhole which sends it back in time. In this scenario, the ball is fired into a wormhole at an angle such that, if it continues along that path, it will exit the wormhole in the past at just the right angle to collide with its earlier self, thereby knocking it off course and preventing it from entering the wormhole in the first place. Physicist Kip Thorne deemed this problem "Polchinski's paradox". Later students of the whimsical problem came up with solutions which managed to avoid any inconsistencies, by having the ball emerge from the future at a different angle than the one used to generate the paradox, and deliver its younger self a glancing blow instead of knocking it completely away from the wormhole, a blow which changes its trajectory in just the right way so that it will travel back in time with the angle required to deliver its younger self this glancing blow.^[1]

Bibliography[link]

• Polchinski, Joseph (1998a), String Theory Vol. I: An Introduction to the Bosonic String, Cambridge University Press, ISBN 0-521-63303-6 
• Polchinski, Joseph (1998b), String Theory Vol. II: Superstring Theory and Beyond, Cambridge University Press, ISBN 0-521-63304-4 

References[link]

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External links[link]

• Personal website

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Andy Strominger at Harvard

Andrew Eben Strominger (born 1955) is an American theoretical physicist who works on string theory and son of Jack L. Strominger. He is currently a professor at Harvard University and a senior fellow at the Society of Fellows. He attended the Cambridge School of Weston for high school, and received his undergraduate degree from Harvard University in 1977, and his Ph.D from the Massachusetts Institute of Technology in 1982 under the supervision of Roman Jackiw. His contributions to physics include:

• a paper with Cumrun Vafa that explains the microscopic origin of the black hole entropy, originally calculated thermodynamically by Stephen Hawking and Jacob Bekenstein, from string theory
• a paper with Philip Candelas, Gary Horowitz, and Edward Witten in the 1980s about the relevance of Calabi-Yau manifolds for obtaining the Standard Model from string theory
• other articles discussing the dS/CFT correspondence (a variation of AdS/CFT correspondence); S-branes (a variation of D-branes)
• OM-theory (with Shiraz Minwalla and Nathan Seiberg)
• noncommutative solitons (with Shiraz Minwalla and Rajesh Gopakumar)
• massless black holes in the form of wrapped D3-branes that regulate the physics of a conifold and allow topology change
• interpretation of mirror symmetry as a special case of T-duality (with Eric Zaslow and Shing-Tung Yau)
• purely cubic action for string field theory
• superstrings with torsion

External links[link]

• Andrew Strominger's home page under construction
• Home page of Strominger at Harvard
• SPIRES database of Strominger's articles

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Sergio Ferrara (born 1945) is an Italian physicist working on theoretical physics of elementary particles and mathematical physics. He is renowned for the discovery of theories introducing supersymmetry as a symmetry of elementary particles (Super-Yang-Mills theories, together with Bruno Zumino ^[1]) and of supergravity, the first significant extension of Einstein's general relativity, based on the principle of "local supersymmetry" (Together with Daniel Z. Freedman, and Peter van Nieuwenhuizen ^[2]). He is a senior staff member at CERN and a professor at the University of California, Los Angeles.

Early years[link]

Sergio Ferrara was born on 2 May 1945 in Rome, Italy. He graduated from the University of Rome in 1968. Since then he has worked as a CNEN and INFN researcher at the Frascati National Laboratories; as a CNRS Visiting Scientist at the Laboratoire de Physique Théorique, École Normale Supérieure, Paris, and at the Theoretical Studies Division at CERN, Geneva.

Supergravity[link]

In 1976, Sergio Ferrara, Daniel Z. Freedman, and Peter van Nieuwenhuizen discovered Supergravity at Stony Brook University in New York. It was initially proposed as a four-dimensional theory. The theory of supergravity generalizes Einstein's theory of general relativity by incorporating the principles of supersymmetry.

Later years[link]

In 1980 he was made a full professor of theoretical physics in Italy. He became a staff member of the Theory Division at CERN in 1981. In 1985, he became a Professor of Physics at the University of California, Los Angeles. Since 1986 he has been a senior staff member of the Physics Department at CERN. He is also Principal Investigator of the European Research Council Advanced Grant SUPERFIELDS.^[3]

Awards[link]

• Dirac Medal, 1993, ICTP, Trieste. (Shared with Daniel Z. Freedman, and Peter van Nieuwenhuizen)

"for their discovery of supergravity theory in 1976 and their major contributions in the subsequent developments of the theory. Their discovery led to an explosion of interest in quantum gravity and it transformed the subject, playing a significant role in very important developments in string theory as well as Kaluza-Klein theory "

• Dannie Heineman Prize for Mathematical Physics, 2006, American Physical Society. (Shared with Daniel Z. Freedman, and Peter van Nieuwenhuizen)

"For constructing supergravity, the first supersymmetric extension of Einstein's theory of general relativity, and for their central role in its subsequent development."

• Enrico Fermi Prize, 2005, Societa' Italiana di Fisica.

"he honoured italian physics with his discoveries, substantially contributing to the discoveries leading to the development of modern gravity theories. For his contribution to the discovery of supergravity theory."

• Amaldi medal, 2008, SIGRAV,

"for his relevant contributions to supergravity models, their matter couplings and their implications for black hole physics, such as the attractor mechanism"

See also[link]

• Supersymmetry
• Supergravity

References[link]

1. ^ S. Ferrara, B. Zumino, Supergauge Invariant Yang-Mills Theories, Nucl.Phys.B79:413,1974
2. ^ D.Z. Freedman, P. van Nieuwenhuizen, S. Ferrara, Progress Toward a Theory of Supergravity, Phys.Rev.D13:3214-3218,1976
3. ^ http://superfields.web.cern.ch/Superfields/

External links[link]

• 2006 Dannie Heineman Prize for Mathematical Physics Recipient
• Sergio Ferrara's profile at UCLA
• SUPERFIELDS web page