The Trouble with de Sitter Space

In this paper we assume the de Sitter Space version of Black Hole Complementarity which states that a single causal patch of de Sitter space is described as an isolated finite temperature cavity bounded by a horizon which allows no loss of information. We discuss the how the symmetries of de Sitter space should be implemented. Then we prove a no go theorem for implementing the symmetries if the entropy is finite. Thus we must either give up the finiteness of the de Sitter entropy or the exact symmetry of the classical space. Each has interesting implications for the very long time behavior. We argue that the lifetime of a de Sitter phase can not exceed the Poincare recurrence time. This is supported by recent results of Kachru, Kallosh, Linde and Trivedi.Comment: 15 pages, 1 figure. v2: added fifth section with comments on long time stability of de Sitter space, in which we argue that the lifetime can not exceed the Poincare recurrence time. v3: corrected a minor error in the appendi

D-Sitter Space: Causal Structure, Thermodynamics, and Entropy

We study the entropy of concrete de Sitter flux compactifications and deformations of them containing D-brane domain walls. We determine the relevant causal and thermodynamic properties of these "D-Sitter" deformations of de Sitter spacetimes. We find a string scale correspondence point at which the entropy localized on the D-branes (and measured by probes sent from an observer in the middle of the bubble) scales the same with large flux quantum numbers as the entropy of the original de Sitter space, and at which Bousso's bound is saturated by the D-brane degrees of freedom (up to order one coefficients) for an infinite range of times. From the geometry of a static patch of D-Sitter space and from basic relations in flux compactifications, we find support for the possibility of a low energy open string description of the static patch of de Sitter space.Comment: 46 pages, harvmac big; 14 figure

Dimensional reduction from entanglement in Minkowski space

Using a quantum field theoretic setting, we present evidence for dimensional reduction of any sub-volume of Minkowksi space. First, we show that correlation functions of a class of operators restricted to a sub-volume of D-dimensional Minkowski space scale as its surface area. A simple example of such area scaling is provided by the energy fluctuations of a free massless quantum field in its vacuum state. This is reminiscent of area scaling of entanglement entropy but applies to quantum expectation values in a pure state, rather than to statistical averages over a mixed state. We then show, in a specific case, that fluctuations in the bulk have a lower-dimensional representation in terms of a boundary theory at high temperature.Comment: 9 pages, changes to presentation, some content corrections, version published in JHE

Comment on "The black hole final state"

Horowitz and Maldacena have suggested that the unitarity of the black hole S-matrix can be reconciled with Hawking's semiclassical arguments if a final-state boundary condition is imposed at the spacelike singularity inside the black hole. We point out that, in this scenario, departures from unitarity can arise due to interactions between the collapsing body and the infalling Hawking radiation inside the event horizon. The amount of information lost when a black hole evaporates depends on the extent to which these interactions are entangling.Comment: 4 pages, REVTe

Flat space physics from holography

We point out that aspects of quantum mechanics can be derived from the holographic principle, using only a perturbative limit of classical general relativity. In flat space, the covariant entropy bound reduces to the Bekenstein bound. The latter does not contain Newton's constant and cannot operate via gravitational backreaction. Instead, it is protected by - and in this sense, predicts - the Heisenberg uncertainty principle.Comment: 11 pages, 3 figures; v2: minor correction

Graviton and Scalar Two-Point Functions in a CDL Background for General Dimensions

We compute the two-point functions of the scalar and graviton in a Coleman-De Luccia type instanton background in general dimensions. These are analytically continued to Lorentzian signature. We write the correlator in a form convenient for examining the "holographic" properties of this background inspired by the work of Freivogel, Sekino, Susskind and Yeh(FSSY). Based on this, we speculate on what kind of boundary theory we would have on this background if we assume that there exists a holographic duality.Comment: 68 pages, 7 figures; typos fixed, error in calculation fixed, discussion adde

Entropic force and its cosmological implications

We investigate a possibility of realizing the entropic force into the cosmology. A main issue is how the holographic screen is implemented in the Newtonian cosmology. Contrary to the relativistic realization of Friedmann equations, we do not clarify the connection between Newtonian cosmology and entropic force because there is no way of implementing the holographic screen in the Newtonian cosmology.Comment: 16 pages, no figures, version "Accepted for publication in Astrophysics & Space Science

The Plasma Puddle as a Perturbative Black Hole

We argue that the weak coupling regime of a large N gauge theory in the Higgs phase contains black hole-like objects. These so-called ``plasma puddles'' are meta-stable lumps of hot plasma lying in locally un-Higgsed regions of space. They decay via O(1/N) thermal radiation and, perhaps surprisingly, absorb all incident matter. We show that an incident particle of energy E striking the plasma puddle will shower into an enormous number of decay products whose multiplicity grows linearly with E, and whose average energy is independent of E. Once these ultra-soft particles reach the interior they are thermalized by the plasma within, and so the object appears ``black.'' We determine some gross properties like the size and temperature of the the plasma puddle in terms of fundamental parameters in the gauge theory. Interestingly, demanding that the plasma puddle emit thermal Hawking radiation implies that the object is black (i.e. absorbs all incident particles), which implies classical stability, which implies satisfaction of the Bekenstein entropy bound. Because of the AdS/CFT duality and the many similarities between plasma puddles and black holes, we conjecture that black objects are a robust feature of quantum gravity.Comment: 23 pages, 3 figures, V2: minor changes, ref added, appendix A.5 moved to body of pape

Black Hole fragmentation and holography

We discuss the entropy change due to fragmentation for black hole solutions in various dimensions. We find three different types of behavior. The entropy may decrease, increase or have a mixed behavior, characterized by the presence of a threshold mass. For two-dimensional (2D) black holes we give a complete characterization of the entropy behavior under fragmentation, in the form of sufficient conditions imposed on the function J, which defines the 2D gravitational model. We compare the behavior of the gravitational solutions with that of free field theories in d dimensions. This excludes the possibility of finding a gravity/field theory realization of the holographic principle for a broad class of solutions, including asymptotically flat black holes. We find that the most natural candidates for holographic duals of the black hole solutions with mixed behavior are field theories with a mass gap. We also discuss the possibility of formulating entropy bounds that make reference only to the energy of a system.Comment: 7 pages, no figure

Is There Really a de Sitter/CFT Duality

In this paper a de Sitter Space version of Black Hole Complementarity is formulated which states that an observer in de Sitter Space describes the surrounding space as a sealed finite temperature cavity bounded by a horizon which allows no loss of information. We then discuss the implications of this for the existence of boundary correlators in the hypothesized dS/cft correspondence. We find that dS complementarity precludes the existence of the appropriate limits. We find that the limits exist only in approximations in which the entropy of the de Sitter Space is infinite. The reason that the correlators exist in quantum field theory in the de Sitter Space background is traced to the fact that horizon entropy is infinite in QFT.Comment: 12 Figures, STIAS Workshop on Quantum Gravit