Entropic N-bound and Maximal Mass Conjecture Violations in Four Dimensional Taub-Bolt(NUT)-dS Spacetimes

TL;DR

This paper demonstrates that certain four-dimensional Taub-Bolt(NUT) de Sitter spacetimes can violate the entropic N-bound and maximal mass conjectures, challenging their universality.

Contribution

It provides the first explicit examples of such violations in four-dimensional Taub-Bolt(NUT) spacetimes with positive cosmological constant.

Findings

Some Taub-Bolt(NUT) spacetimes have higher entropy than de Sitter space.

Violations of the maximal mass conjecture are demonstrated.

The results are based on an extended path integral approach for asymptotically de Sitter spaces.

Abstract

We show that the class of four-dimensional Taub-Bolt(NUT) spacetimes with positive cosmological constant for some values of NUT charges are stable and have entropies that are greater than that of de Sitter spacetime, in violation of the entropic N-bound conjecture. We also show that the maximal mass conjecture, which states "any asymptotically dS spacetime with mass greater than dS has a cosmological singularity", can be violated as well. Our calculation of conserved mass and entropy is based on an extension of the path integral formulation to asymptotically de Sitter spacetimes.