The Einstein-Hilbert action represents the simplest generally covariant formulation of gravity. Despite the success of Einstein' s field equations across a wide range of scales, theoretical motivations, including insights from quantum gravity, string theory, and effective field theory suggest that the classical theory may be incomplete. These considerations naturally lead to the inclusion of higher curvature invariants as corrections to the Einstein-Hilbert action. In this seminar, I will provide an overview of the rationale behind such modifications and examine their physical implications. Particular emphasis will be placed on the challenges posed by higher curvature terms, including potential violations of causality and issues of classical and quantum stability. The goal is to assess the viability of these extended theories and their prospects for providing a consistent extension of general relativity.

Biography

Sudipta Sarkar is a Professor of Physics at the Indian Institute of Technology (IIT) Gandhinagar, India. He obtained his Ph.D. from the Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune, and subsequently conducted postdoctoral research at the University of Maryland, USA. His research interests lie primarily in gravitation, gravitational waves, and black hole physics. He is visiting the Institute of Theoretical Physics as a Peng Huanwu Visiting Professor.

Inviter: Li Li