A Review of the N-bound and the Maximal Mass Conjectures Using NUT-Charged dS Spacetimes

Abstract

The proposed dS/CFT correspondence remains an intriguing paradigm in the context of string theory. Recently it has motivated two interesting conjectures: the entropic N-bound and the maximal mass conjecture. The former states that there is an upper bound to the entropy in asymptotically de Sitter spacetimes, given by the entropy of pure de Sitter space. The latter states that any asymptotically de Sitter spacetime cannot have a mass larger than the pure de Sitter case without inducing a cosmological singularity. Here we review the status of these conjectures and demonstrate their limitation. We first describe a generalization of gravitational thermodynamics to asymptotically de Sitter spacetimes, and show how to compute conserved quantities and gravitational entropy using this formalism. From this we proceed to a discussion of the N-bound and maximal mass conjectures. We then illustrate that these conjectures are not satisfied for certain asymptotically de Sitter spacetimes with NUT charge. We close with a presentation of explicit examples in various spacetime dimensionalities.

49 pages, 17 figures, a few typos corrected, addendum added with regard to some references that were later brought to our attention

References in corpus (3)

• Accelerating Universes and String Theory
• Entropic N-bound and Maximal Mass Conjecture Violations in Four Dimensional Taub-Bolt(NUT)-dS Spacetimes
• Mass, Action and Entropy of Taub-Bolt-dS Spacetimes

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• New Taub-NUT-Reissner-Nordström spaces in higher dimensions
• Hidden Conformal Symmetry of Extremal Kerr-Bolt Spacetimes
• Entropy and Mass Bounds of Kerr-de Sitter Spacetimes
• On the Thermodynamics of 5D Black Holes on ALF Gravitational Instantons
• Cosmological monopoles and non-abelian black holes
• Holography in Three-dimensional Kerr-de Sitter Space with a Gravitational Chern-Simons Term
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• Consistent mass formulas for higher even-dimensional Reissner-Nordström-NUT-AdS spacetimes
• Thermodynamic Volume of Cosmological Solitons