Cosmologist Matias Zaldarriaga Appointed to the Faculty of the Institute for Advanced Study

Princeton, N.J., February 17, 2009 - Theoretical astrophysicist and cosmologist Matias Zaldarriaga will join the Faculty at the Institute for Advanced Study, effective July 1, 2009. Dr. Zaldarriaga comes to the Institute's School of Natural Sciences from Harvard University, where he is currently a professor in the departments of astronomy and physics. Dr. Zaldarriaga will succeed astrophysicist Peter Goldreich, who joined the Faculty in 2004 and who will retire on June 30, 2009.

Dr. Zaldarriaga, one of the leading theoretical cosmologists of his generation, has made many influential and creative contributions to our understanding of the early universe, particle astrophysics and cosmology as a probe of fundamental physics. Much of his work centers on the recent remarkable discovery that the expansion of the universe is accelerating, rather than decelerating as would be expected if gravity were the dominant long-range force in the universe. He first became known for the development of an extremely fast numerical technique for calculating the properties of small fluctuations in Cosmic Microwave Background (CMB) that probe the properties of the early universe. He developed this technique in 1996 while a first-year graduate student at Massachusetts Institute of Technology, working with Uros Seljak, who was then a post-doctoral student at Harvard. Their method, called CMBFAST, accelerated calculations of CMB fluctuations by some two orders of magnitude, making all previous codes obsolete.

Peter Goddard, Director of the Institute, stated, "We are delighted that Matias Zaldarriaga will be joining the Faculty of the Institute. He has added greatly to our understanding of the microwave background, and he combines great breadth and depth in his research with the ability to find simple and elegant solutions to complicated problems, leading to results that are practically useful. His presence on the Faculty will increase even more the growing interaction between the astrophysicists and the particle physicists working at the Institute."

"The very strong astrophysics and particle physics efforts at the Institute provide the ideal environment for my research," said Dr. Zaldarriaga. "I am eager to join the Institute this July and look forward to many exciting years on the Faculty."

Dr. Zaldarriaga's recent research has focused on intergalactic hydrogen gas in the early universe, before galaxy and star formation was underway. He is one of the leading theorists developing machinery to study this gas using the spectral line from neutral hydrogen at 21-centimeter wavelength. While the idea of using 21-cm radiation to probe the history of the universe dates back some two decades, Dr. Zaldarriaga's work has emphasized the strong analogy between 21-cm fluctuations and CMB fluctuations, and the importance of using statistical techniques to study these fluctuations. His insights have been largely responsible for igniting the enthusiasm of the large community of CMB theorists and experimentalists who are now working with this challenging but potentially transformative new technique.

In his study of the early universe, he has proposed qualitatively new ways of driving inflation and generating density perturbations. He has also investigated more formal issues in cosmology, including a proposed alternative to inflation, the "bouncing cyclic universe." Working with Paolo Creminelli and Alberto Nicolis, he showed that it is possible to make predictions for density perturbations that are independent of the details of the bouncing phase.

"Matias combines great creativity, formidable technical power and a deep understanding of the experimental landscape and data analysis," commented Scott Tremaine, Richard Black Professor in the School of Natural Sciences. "He is uniquely able to exploit the growing connections between astrophysics and particle physics and to link the ongoing research efforts in these two disciplines at the Institute."

Born in Argentina, Dr. Zaldarriaga earned his undergraduate degree in physical science from the University of Buenos Aires in 1994. In 1998, he obtained a Ph.D. in physics from Massachusetts Institute of Technology (MIT). He was a long-term Member at the Institute from 1998 to 2001, and served as W. M. Keck Visiting Associate in Cosmology at the Institute from 2001 to 2002. He moved to New York University in 2003 as an assistant professor, and the following year he joined Harvard University as associate professor. In 2004, he became professor at Harvard, with appointments in both the departments of astronomy and physics.

Dr. Zaldarriaga is the recipient of a 2006 MacArthur Fellowship. In 2005, he was awarded the Gribov Medal, which is presented every two years by the European Physical Society to recognize a young physicist for outstanding work performed in the field of theoretical particle physics and/or field theory. The American Astronomical Society awarded him its 2003 Helen B. Warner Prize for Astronomy, and he received a David and Lucile Packard Fellowship in 2001 and a Hubble Fellowship in 1998. While a student at MIT, he was awarded the Barrett Prize for originality in astrophysics research.

Dr. Zaldarriaga has maintained a close relationship with the Institute since his postdoctoral days, spending time as a visitor in the School of Natural Sciences in 2004, 2005 and 2008.

About the Institute for Advanced Study

The Institute for Advanced Study is one of the world’s leading centers for theoretical research and intellectual inquiry. The Institute exists to encourage and support curiosity-driven research in the sciences and humanities—the original, often speculative thinking that produces advances in knowledge that change the way we understand the world. Work at the Institute takes place in four Schools: Historical Studies, Mathematics, Natural Sciences and Social Science. It provides for the mentoring of scholars by a permanent Faculty of approximately 30, and it ensures the freedom to undertake research that will make significant contributions in any of the broad range of fields in the sciences and humanities studied at the Institute.

The Institute, founded in 1930, is a private, independent academic institution located in Princeton, New Jersey. Its more than 6,000 former Members hold positions of intellectual and scientific leadership throughout the academic world. Thirty-three Nobel Laureates and 40 out of 56 Fields Medalists, as well as many winners of the Wolf and MacArthur prizes, have been affiliated with the Institute.