GRG Editor's Choice: Null boundary terms for Lanczos–Lovelock gravity

© SpringerChakraborty, S. & Parattu, K., Null boundary terms for Lanczos–Lovelock gravity, Gen Relativ Gravit (2019) 51: 23.

Editor's Choice (Research Article)

First Online: 01 February 2019

"The authors analyze in a very detailed way the variation of the Lovelock gravitational action when null boundaries are present and they construct a boundary term that ensures that the variational problem is well-posed. As far as I know, this is the first time this boundary term is computed in full generality. The topic is interesting since these null boundary terms are necessary in order to perform a general study of the Complexity=Action proposal for Lovelock gravity."


We derive boundary terms appropriate for the general Lanczos–Lovelock action on a null boundary, when Dirichlet boundary conditions are imposed. We believe that these boundary terms have been derived for the first time in the literature. In this derivation, we rely only on the structure of the boundary variation of the action for Lanczos–Lovelock gravity. We also provide the null boundary term for Gauss–Bonnet gravity separately.

The authors: 

Sumanta Chakraborty is an a INSPIRE Faculty Fellow at the Indian Association for the Cultivation of Science (IACS), Kolkata, India. He is working on gravitational physics, and has elaborated to various possible branches and in particular to theories at the interface of gravity and quantum. His thesis on "Classical and Quantum Aspects of Gravity in Relation to the Emergent Paradigm" (2017) has been published in the Springer Theses series, which is recognizing outstanding PhD research.

Krishnamohan Parattu is a Postdoctoral Fellow at the Indian Institute of Technology (IIT) Madras, Chennai, India. He is working on the theory of gravity. 

Both authors have earned their PhD degrees under the supervision of Prof. Thanu Padmanabhan, with whom they collaborated on the highly-cited paper "A boundary term for the gravitational action with null boundaries" [Gen Relativ Gravit (2016) 48: 94].

GRG Editor's Choice:

In each volume of GRG, a few papers are marked as “Editor’s Choice”. The primary criteria is original, high quality research that is of wide interest within the community.