Holography at an Extremal De Sitter Horizon

TL;DR

This paper demonstrates that the near-horizon region of extremal rotating black holes in de Sitter space exhibits a Virasoro algebra, suggesting a duality with a 2D conformal field theory, extending Kerr/CFT ideas to cosmological horizons.

Contribution

It shows the asymptotic symmetry group of extremal rotating de Sitter black holes includes a Virasoro algebra, indicating a holographic duality with a 2D CFT, distinct from previous Kerr/CFT models.

Findings

Virasoro algebra with positive central charge at the de Sitter horizon

Evidence for duality between quantum gravity in Nariai background and 2D CFT

Differences from Kerr/CFT include cosmological horizon instead of event horizon

Abstract

Rotating maximal black holes in four-dimensional de Sitter space, for which the outer event horizon coincides with the cosmological horizon, have an infinite near-horizon region described by the rotating Nariai metric. We show that the asymptotic symmetry group at the spacelike future boundary of the near-horizon region contains a Virasoro algebra with a real, positive central charge. This is evidence that quantum gravity in a rotating Nariai background is dual to a two-dimensional Euclidean conformal field theory. These results are related to the Kerr/CFT correspondence for extremal black holes, but have two key differences: one of the black hole event horizons has been traded for the cosmological horizon, and the near-horizon geometry is a fiber over dS_2 rather than AdS_2.