UNIVERSITY PARK, Pa. — Penn State Professor of Physics Abhay Ashtekar, holder of the Eberly Family Chair in Physics and director of the Penn State Institute for Gravitation and the Cosmos, has been elected as a member of the National Academy of Sciences. Election to membership in the academy is one of the highest honors accorded to U.S. scientists or engineers by their peers.
Ashtekar's research focuses on classical general relativity and quantum gravity. Thanks to his groundbreaking work, loop quantum gravity — a quantum theory of spacetime — has become a leading approach to the unification of general relativity and quantum physics that is being pursued in dozens of research groups worldwide. Ashtekar has continued to play a seminal role in the development of this field, as well as its sub-field, loop quantum cosmology. Ashtekar also has made contributions to quantum field theory, gauge theories, general relativity, and gravitational-wave science. In broad terms, his contributions are at the interface between geometry and physics.
In a summary of Ashtekar's contributions to science, the National Academy of Sciences notes, "Ashtekar launched Loop Quantum Gravity by introducing new variables to simplify Einstein’s equations. Subsequently, his group developed the theory of quantum Riemannian geometry to describe 'atoms of geometry.' Space-time can be visualized as a fabric that is woven by one-dimensional quantum threads. Thanks to this specific microscopic description, the big bang of general relativity is tamed and replaced by a big bounce. Consequently, there are no infinities and one can study the very early universe unambiguously. This theory has been developed in detail, shown to make predictions that are borne out by the cosmic microwave background missions, and also has made predictions for future observations. It brings out an unforeseen relation between the very small and the very large. Ashtekar and his team also have analyzed global problems in general relativity. They developed the notion of quasi-local horizons that is widely used in numerical simulations of black hole collisions, as well as in the investigations of the quantum-mechanical evaporation of black holes. On another front, they have shown that the presence of a cosmological constant introduces unforeseen issues in the theory of gravitational waves and constructed a framework to address them."
Renowned as one of the most-cited researchers in the field of relativity, Ashtekar has given more than 160 plenary lectures at national and international conferences and workshops. Ashtekar was honored at the Loops 11 Conference "Celebrating 25 years of Loop Quantum Gravity," which in 2011 commemorated the 25th anniversary of the publication of his landmark scientific paper about loop quantum gravity that sparked a revolution within the field of spacetime physics. His previous awards and recognitions include honorary doctoral degrees from the Université de la Méditerranée in Aix-Marseille, France, in 2010 and from the Friedrich Schiller University in Jena, Germany, in 2005. In addition, in 2004, he received a Forschungspreis Award from the Alexander von Humboldt Foundation in Germany. He has written or co-written more than 260 scientific papers and written or co-edited nine scientific books. He has served on the editorial boards of all the major journals in his field.
Ashtekar is a Fellow of the American Association for Advancement of Science and the American Physical Society. He is one of only 51 Honorary Fellows of the Indian Academy of Sciences drawn from the community of scientists living outside of India. He has held the Krammers Visiting Chair in Theoretical Physics at the University of Utrecht, Netherlands; a senior visiting fellowship of the British Science and Engineering Research Council; and the Sir C. V. Raman Chair of the Indian Academy of Science. In addition, he holds a visiting professorship at the Beijing Normal University and at the Inter-University Center for Astronomy and Astrophysics in Pune, India.
Ashtekar's research also has been described widely in popular and semi-popular media, sometimes as cover stories. Publications and media outlets that have reported on his research include Nature, Science, The Economist, U.S. News and World Report, The New York Times, New Scientist, Fox News, MSNBC, and many other international publications and news sources. In addition, Ashtekar was featured in the 2008 German documentary Kosmos, which was prepared in celebration of German physicist Max Planck's 150th birthday. He also was featured prominently in a documentary shown at the yearlong Berlin Einstein Exhibit in 2005.
Before joining the faculty at Penn State, Ashtekar held positions as professor, distinguished professor, and the Erastus Franklin Holden Professor of Physics at Syracuse University from 1984 to 1993. Previously, he was professor and chair of gravitation at the University of Paris VI in France.
The National Academy of Sciences is a private organization of scientists and engineers dedicated to the furtherance of science and its use for the general welfare. It was established in 1863 by a congressional act of incorporation, signed by Abraham Lincoln, which calls on the academy to act as an official adviser to the federal government, upon request, in any matter of science or technology.