Cumrun Vafa

Vafa says he was born in Tehran, Iran, in 1960, and that his parents were born in Zanjan, a Turkish-speaking region of Iran.⁠[1]

He attended Alborz high school, one of Iran’s best, and recalls that the whole country then used a single science textbook and lagged the West in science education, so he taught himself topics such as special relativity.⁠[2]

Applying to US colleges a year early, he entered the Massachusetts Institute of Technology in 1977 planning to study engineering and economics, switched to math and physics in his second year, and graduated in 1981 with a double major.⁠[2]

He then went to Princeton UniversityPrinceton UniversityPrinceton University is a private university and Ivy League member in Princeton, New Jersey. Chartered on October 22, 1746 as the College of New Jersey, it moved to Princeton in 1756 and adopted its present name in 1896. Undergraduate education leads to A.B. and B.S.E. degrees and emphasizes small-group discussion, independent research and residential college life. Graduate education spans the humanities, social sciences, natural sciences and engineering. As of October 2026, Christopher L. Eisgruber was president. Its 2026–27 operating budget was $3.407 billion, including $342 million for undergraduate aid.Open the full entry, earning a PhD in physics in 1985 under Edward Witten, and became a Junior Fellow of the Harvard Society of Fellows that year.⁠[3]

He recalls choosing Princeton to work with the rising star Witten, who also nominated him to the Harvard Society of Fellows.⁠[1]

In 1990 he was appointed full professor in Harvard University’s physics department, later becoming Donner Professor of Science; his research centers on string theory and its applications to quantum field theory and quantum gravity.⁠[3]

In February 1996 he posted the paper Evidence for F-Theory, constructing compact examples of D-manifolds for type IIB strings and interpreting them as compactifications of a 12-dimensional “F-theory.”⁠[4]

He is one of the founders of the duality revolution in string theory and has used topological aspects of string theory to study black holes.⁠[5]

In September 2005 he published The String Landscape and the Swampland, proposing that the landscape of string vacua is surrounded by an even vaster “swampland” of consistent-looking semiclassical effective field theories that are actually inconsistent, and suggesting finiteness criteria to help locate the boundary.⁠[6]

The ICTP awarded the 2008 Dirac Medal to Juan Martin Maldacena, Joseph Polchinski and Vafa for fundamental contributions to superstring theory, from orbifold compactifications and mirror symmetry to D-branes, black hole physics and gauge theory–gravity correspondence; at the June 19, 2009, ceremony he gave the Dirac Lecture “Stringy Predictions for Particle Physics.”⁠[7]

During Stephen Hawking’s April 2016 visit to Harvard, Vafa hosted a dinner in his honor at his home in Newton, entertaining Hawking and a group of about 70, many from Harvard’s physics department, with Persian food and traditional folk songs.⁠[8]

He shared the 2017 Breakthrough Prize in Fundamental Physics with Joseph Polchinski and Andrew StromingerAndrew StromingerAndrew Strominger is an American theoretical physicist and Gwill E. York Professor of Physics at Harvard University who works on quantum gravity, string theory and black holes; with collaborators he introduced Calabi–Yau compactifications of string theory, and with Cumrun Vafa he derived the Bekenstein–Hawking black hole entropy by counting microscopic states, and his honours include the Breakthrough Prize in Fundamental Physics.Open the full entry “for transformative advances in quantum field theory, string theory, and quantum gravity”; all three are ICTP Dirac Medalists, and Vafa sits on the ICTP Scientific Council.⁠[9]

In his prize statement he thanked more than 150 collaborators and his thesis supervisor Witten, cited his birthplace Iran and figures such as Khayyam and Biruni, dedicated the prize to his wife Afarin, and said his three sons had brought joy and meaning to his life.⁠[10]

In 2017, as Donner Professor of Science, he was among the recipients of the Ellis Island Medal of Honor, created in 1986 and presented each year on Ellis Island to people recognized for accomplishments in their fields and service to the nation.⁠[11]

The news section of his website lists his 2018 appointment as Harvard’s Hollis Professor of Mathematicks and Natural Philosophy.⁠[12]

In June 2018 he, Georges Obied, Hirosi Ooguri and Lev Spodyneiko published De Sitter Space and the Swampland, proposing that the scalar potential of any consistent quantum gravity theory must satisfy |∇V| ≥ c·V, which forbids metastable de Sitter vacua.⁠[13]

He presented the conjecture at the Strings 2018 conference in Okinawa, Japan, setting off debate; the conjecture requires the vacuum energy to decrease, so if it is correct the cosmos must be profoundly different than supposed or string theory must be wrong.⁠[14]

Since 2012 he has taught the Harvard freshman seminar “Physics, Math and Puzzles,” using puzzles to explain physics and math; in 2020 he collected about 70 of the course’s puzzles in Puzzles to Unravel the Universe, a book for general readers.⁠[15]

On July 26, 2021, he appeared on episode 204 of the Lex FridmanLex FridmanLex Fridman is a Soviet-born, US-raised computer scientist and podcast host who works as an MIT research scientist on human-AI interaction and autonomous driving. His Lex Fridman Podcast is known for hours-long conversations with guests including heads of state and technology leaders.Open the full entry Podcast, discussing the difference between math and physics, quantum mechanics, quantum gravity, string theory and extra dimensions, skepticism about string theory, Edward Witten, and the string landscape and swampland.⁠[16]

On October 21, 2021, Iran awarded him the Mustafa Prize in the category “All Areas of Science and Technology,” worth $500,000; he said the award reminded him that science and technology have no borders, and donated it to an Iranian science foundation.⁠[17]

On May 16 and 17, 2022, as Hollis Professor, he gave the Della Pietra lectures at the Simons Center for Geometry and Physics at Stony Brook, including a public lecture based on his book and a session for high school students.⁠[18]

In May 2022 he, Miguel Montero and Irene Valenzuela published The Dark Dimension and the Swampland, combining swampland principles with the smallness of dark energy to predict an extra “dark dimension” of roughly micron scale and a tower of light states.⁠[19]

He has called the cosmological constant “the smallest measured parameter in physics,” and from that he and his two collaborators inferred that one of string theory’s extra dimensions must be significantly larger than the others.⁠[20]

On October 29, 2025, Harvard announced that Vafa, then Hollis Professor and chair of the Department of Physics, had been appointed Timken University Professor; University Professorships are Harvard’s highest faculty distinction, and the Timken chair honors a distinguished scholar in any field of science.⁠[21]

Responding to the phantom behavior of dark energy suggested by DESI data, he said the assumption that dark energy can be computed independently of dark matter is wrong; he and collaborators had earlier proposed that dark matter particle masses may vary over time and in 2022 linked dark matter and dark energy to the dark dimension.⁠[22]

As of October 2026 he is Timken University Professor in Harvard’s physics department and a member of the National Academy of Sciences and the American Academy of Arts and Sciences, and has received prizes for mathematical physics from the American Mathematical Society and the American Physical Society.⁠[5]

Personal website: Public link: https://www.cumrunvafa.org/ (opens in a new window)⁠[16]

X: Public account: https://x.com/cumrunv (opens in a new window)⁠[16]

Harvard University: Official website: https://www.harvard.edu/ (opens in a new window)⁠[21]