Abhay V. Ashtekar

The Pennsylvania State University

Primary Section: 13, Physics
Secondary Section: 12, Astronomy
Membership Type: Member (elected 2016)


Abhay Ashtekar is the Director of the Institute for Gravitation and the Cosmos, Evan Pugh Professor of Physics and and holder of the Eberly Chair in Physics at Penn State. Before joining Penn State he was the Erasthus Franklin Holden Professor of Physics at Syracuse University and Professeur (Chaire de Gravitation) at Paris VI.  He was awarded Doctor Rerum Naturalium Honoris Causa by the Friedrich-Schiller Universite at, Jena, Germany in 2005 and by the Universite de Aix-Marseille II, France in 2010. He is a past President of the International Society for General Relativity and Gravitation.  He is a Fellow of the American Association for Advancement of Science and one of only 40 Honorary Fellows of the Indian Academy of Sciences drawn from the International community. He won the Einstein Prize of the American Physical Society and a Senior Forschungspreis of the Alexander von Humboldt Foundation. He has held the Krammers Visiting Chair in Theoretical Physics at the University of Utrecht, The Netherlands and the Sir C. V. Raman Chair of the Indian Academy of Science. He Chairs the International Advisory Committee of the Indigo Consortium in connection with the LIGO-India initiative.

Research Interests

Ashtekar’s group developed the theory of quantum Riemannian geometry that lies at the foundation of Loop Quantum Gravity. It describes '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 has also made predictions for future observations. It brings out an unforeseen relation between the very small and the very large. Ashtekar and his team have also 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. In broad terms, these diverse projects explore the interface of physics and geometry.

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