Vaibhav Kalvakota

Vaibhav Kalvakota

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Writings

The Definition of Holography

June 30, 2024

Talk, Theoretical Nexus, Online

In this talk, we will review the notion of holography in quantum gravity. We will discuss some subtleties around the definition of holography, and the implications of holography. In the first half, we will discuss some elementary aspects of (A)dS/CFT, some comparisons, and how certain technicalities complicate the general notion of holography as a bulk-(cutoff-)boundary duality. In the second half, we will discuss some aspects in more technical detail, especially in the direction of establishing holography mathematically.

Holographic Quantum Gravity and Horizon Instability

July 12, 2023

Conference talk, International Conference on New Frontiers in Physics 2023, Crete, Greece

In this talk, we will look at the relation between the No Transmission principle and the Strong cosmic censorship (SCC), which we will highlight in the background of quantum gravity. We show that taking quantum gravity into account, one can provide a complete picture of the instability of the inner horizon and the principle that two independent CFTs, under the gauge-gravity duality, imply that the dual bulks must also be independent in that there must not exist a way to transmit a signal between the two spacetimes. We show that this can simply be interpreted as SCC, and that the inner horizon must be unstable (at either linear or nonlinear orders) to be in accordance with holographic quantum gravity.

Aspects of the Generalized Second Law and the Covariant Entropy bound

March 01, 2023

Talk, ICTS-TIFR Strings talk, Bangalore, India

In this talk, we will look at generalized entropy and the generalized second law in the perspective of singularities. We will review the GSL in a cosmological perspective, and find motivation towards the GSL and entropy based singularity theorems. We will see how the fine-grained GSL and the covariant entropy bound provide a physical tool for singularity theorems, replacing topological conditions such as the presence of a non-compact Cauchy surface with instead the quantum focusing conjecture. We will then discuss further aspects of the GSL such as quantum holographic screens in different cosmologies, and if time permits we will provide an outlook for the role of generalized entropy in the asymptotic nature of null hypersurfaces, which will formulate a quantum Penrose inequality for null hypersurfaces on the basis of the generalized entropy. Recording available at https://www.youtube.com/watch?v=dH2IhL_s3o8.