ICTS

Education:

PhD (Harvard, 2008)

Research Interests

Suvrat Raju's research focuses on quantum gravity and quantum field theory. 

Quantum gravity has brought modern physics to an unusual position. Although in most physical problems it is possible to find several theories that are internally consistent, only one of them is externally consistent i.e. describes how nature works. However, putting together the general theory of relativity, which describes classical gravity, and quantum mechanics creates so many puzzles and paradoxes that it is hard to find even one internally consistent theory.

The first problem is that quantum gravity predicts the existence of "gravitons" which are particles associated with gravity-waves, just like photons are associated with light-waves. But, naively, the amplitude for two of these gravitons to scatter off each other grows too fast to be consistent with quantum mechanics. This problem was solved by the advent of perturbative string theory.

However, the introduction of black holes creates further puzzles. Black-holes are regions of spacetime, from which even light cannot escape. Can we say anything about the nature of this region of space? Moreover, it is known that, quantum mechanically, black holes evaporate. Quantum mechanics also tells us that this process should be reversible but, a naive analysis suggests that, as the black hole evaporates it loses memory about its initial state. This is called the information paradox.

The research group at ICTS, including Prof. Raju and a number of students and postdoctoral researchers, has developed a novel approach to the information paradox by showing that gravity localizes information unusually. So, even as matter falls into a black hole, it leaves behind an imprint on the quantum state outside the black hole that affects black-hole evaporation and preserves information. This also leads to new possibilities for reformulating gravity in asymptotically flat space.

Prof. Raju is also interested in theoretically understanding quantum gravity in de Sitter space. This is a question that is relevant for early Universe cosmology. 

More recently, Prof. Raju has been interested in the interplay between artificial intelligence and physics. A physics-inspired approach might help to develop a theoretical understanding of why artificial intelligence models work so well and applying these models to physics might result in new scientific insights. 

Selected Publications:

1. Suvrat Raju, ``Lessons from the Information Paradox'',  eprint: arxiv:2012.05770

2. Alok Laddha, Siddharth G. Prabhu, Suvrat Raju, Pushkal Shrivastava, "The Holographic Nature of Null Infinity", e-print: arXiv:2002.02448.

3. Tuneer Chakraborty, Joydeep Chakravarty,Victor Godet,Priyadarshi Paul, Suvrat Raju, Holography of information in de Sitter space, eprint: arXiv: 2303.16516.

4. Kyriakos Papadodimas, Suvrat Raju "An Infalling Observer in AdS/CFT", e-print: arXiv:1211.6767

5. Suvrat Raju, "New Recursion Relations and a Flat Space Limit for AdS/CFT Correlators", eprint: arXiv:1201.6449

6. Suvrat Raju and Praneeth Netrapalli, "A model of errors in transformers", arXiv:2601.14175