This paper explores infrared quantum effects in the de Sitter space. The notion of ”eternal manifolds” is introduced and it is shown that in most cases the de Sitter space doesn’t belong to this class. It is unstable under small perturbations which may cause a breakdown of the de Sitter symmetry. The de Sitter string sigma model is discussed. It is argued that the gauge theory at the complex co...

A relation between the Friedmann equation and the Cardy formula has been found for de Sitter closed and Anti de Sitter flat universes. For the remaining (Anti) de Sitter universes the arguments fail, and we speculate whether the general philosophy of holography can be satisfied in such contents. PACS number(s): 04.70.Dy, 98.80.Cq e-mail:[email protected] e-mail:[email protected] e-mail...

It has been recently pointed out that black holes of constant curvature with a “chronological singularity” can be constructed in any spacetime dimension. These black holes share many common properties with the 2+1 black hole. In this contribution we give a brief summary of these new black holes and consider them as solutions of a Chern-Simons gravity theory. We also provide a brief introduction...

We give a Hamiltonian definition of mass for asymptotically hyperboloidal Riemannian manifolds, or for spacelike hypersurfaces in space-times with metrics which are asymptotic to the anti-de Sitter one.

I will describe recent evidence that anti-de Sitter spacetime is nonlinearly unstable. Generic small but finite perturbations eventually form small black holes. I will also present evidence that there are special solutions, called geons, which remain close to anti-de Sitter. I will argue that one can put black holes inside the geons to obtain a family of black holes in anti-de Sitter spacetime ...

Every de Sitter vacuum can transition to every other de Sitter vacuum despite any obstacle, despite intervening anti-de Sitter sinks, despite not being connected by an instanton. Eternal inflation populates the whole landscape.

We consider the non-interacting massive Wess-Zumino model in four-dimensional anti-de Sitter space and show that the conformal dimensions of the corresponding boundary fields do not always satisfy the relation expected from superconformal invariance.

We study the energy density and pressure of a relativistic thermal gas of massless fermions on four-dimensional Minkowski and anti-de Sitter space-times using relativistic kinetic theory. The corresponding quantum field theory quantities are given by components of the renormalized expectation value of the stress-energy tensor operator acting on a thermal state. On Minkowski space-time, the reno...

This paper is based on a talk given by the author at the BEEMFEST, held at the University of Missouri, Columbia, in May, 2003. It was indeed a great pleasure and priviledge to participate in this meeting honoring John Beem, whose many oustanding contributions to mathematics, and leadership in the field of Lorentzian geometry has enriched so many of us. In this paper we present some results, bas...

Synthesizing older ideas about the 1/N expansion in gauge theory, the quantum mechanics of black holes, and quantum field theory in Anti de Sitter space, a new correspondence between gauge theory and quantum gravity has illuminated both subjects.