Results 1  10
of
199
The holographic principle
 Rev. Mod. Phys
, 2002
"... There is strong evidence that the area of any surface limits the information content of adjacent spacetime regions, at 1.4 ×10 69 bits per square meter. We review the developments that have led to the recognition of this entropy bound, placing special emphasis on the quantum properties of black hole ..."
Abstract

Cited by 132 (9 self)
 Add to MetaCart
(Show Context)
There is strong evidence that the area of any surface limits the information content of adjacent spacetime regions, at 1.4 ×10 69 bits per square meter. We review the developments that have led to the recognition of this entropy bound, placing special emphasis on the quantum properties of black holes. The construction of lightsheets, which associate relevant spacetime regions to any
The annular report on noncritical string theory
, 2003
"... Recent results on the annulus partition function in Liouville field theory are applied to noncritical string theory, both below and above the critical dimension. Liouville gravity coupled to c ≤ 1 matter has a dual formulation as a matrix model. Two wellknown matrix model results are reproduced pr ..."
Abstract

Cited by 121 (5 self)
 Add to MetaCart
(Show Context)
Recent results on the annulus partition function in Liouville field theory are applied to noncritical string theory, both below and above the critical dimension. Liouville gravity coupled to c ≤ 1 matter has a dual formulation as a matrix model. Two wellknown matrix model results are reproduced precisely using the worldsheet formulation: (1) the correlation function of two macroscopic loops, and (2) the leading nonperturbative effects. The latter identifies the eigenvalue instanton amplitudes of the matrix approach with disk instantons of the worldsheet approach, thus demonstrating that the matrix model is the effective dynamics of a Dbrane realization of d ≤ 1 noncritical string theory. In the context of string theory above the critical dimension, i.e. d ≥ 25, Liouville field theory realizes twodimensional de Sitter gravity on the worldsheet. In this case, appropriate Dbrane boundary conditions on the annulus realize the Smatrix for twodimensional de Sitter gravity.
String propagation in the presence of cosmological singularities, JHEP 0206
, 2002
"... We study string propagation in a spacetime with positive cosmological constant, which includes a circle whose radius approaches a finite value as t  → ∞, and goes to zero at t = 0. Near this cosmological singularity, the spacetime looks like IR 1,1 / Z. In string theory, this spacetime must be ex ..."
Abstract

Cited by 67 (2 self)
 Add to MetaCart
(Show Context)
We study string propagation in a spacetime with positive cosmological constant, which includes a circle whose radius approaches a finite value as t  → ∞, and goes to zero at t = 0. Near this cosmological singularity, the spacetime looks like IR 1,1 / Z. In string theory, this spacetime must be extended by including four additional regions, two of which are compact. The other two introduce new asymptotic regions, corresponding to early and late times, respectively. States of quantum fields in this spacetime are defined in the tensor product of the two Hilbert spaces corresponding to the early time asymptotic regions, and the Smatrix describes the evolution of such states to states in the tensor product of the two late time asymptotic regions. We show that string theory provides a unique continuation of wavefunctions past the cosmological singularities, and allows one to compute the Smatrix. The incoming vacuum evolves into an outgoing state with particles. We also discuss instabilities of asymptotically timelike linear dilaton spacetimes, and the question of holography in such spaces. Finally, we briefly comment on the relation of our results to recent discussions of de Sitter space.
Strings in homogeneous gravitational waves and null holography
 JHEP 0208
"... Abstract: Homogeneous gravitational wave backgrounds arise as infinite momentum limits of many geometries with a wellunderstood holographic description. General global aspects of these geometries are discussed. Using exact CFT techniques, strings in ppwave backgrounds supported by a NeveuSchwarz ..."
Abstract

Cited by 50 (4 self)
 Add to MetaCart
(Show Context)
Abstract: Homogeneous gravitational wave backgrounds arise as infinite momentum limits of many geometries with a wellunderstood holographic description. General global aspects of these geometries are discussed. Using exact CFT techniques, strings in ppwave backgrounds supported by a NeveuSchwarz flux are quantized. As in Euclidean AdS3, spectral flow and associated long strings are shown to be crucial in obtaining a complete spectrum. Holography is investigated in such backgrounds, using conformally flat coordinates analogous to those of the Poincaré patch in AdS. It is argued that the holographic direction is the lightcone null coordinate u. It is proposed that the holographic degrees of freedom live on a codimensionone screen at fixed u (possibly dimensionally reduced due to the confining harmonic potentiel in transverse space). A complementary screen at fixed v is argued to be necessary in order to encode the vacuum structure. Contents
de Sitter holography and the cosmic microwave background
 JHEP
, 2002
"... Abstract: We interpret cosmological evolution holographically as a renormalisation group flow in a dual Euclidean field theory, as suggested by the conjectured dS/CFT correspondence. Inflation is described by perturbing around the infrared fixed point of the dual field theory. The spectrum of the c ..."
Abstract

Cited by 34 (8 self)
 Add to MetaCart
(Show Context)
Abstract: We interpret cosmological evolution holographically as a renormalisation group flow in a dual Euclidean field theory, as suggested by the conjectured dS/CFT correspondence. Inflation is described by perturbing around the infrared fixed point of the dual field theory. The spectrum of the cosmic microwave background radiation is determined in terms of scaling violations in the field theory. The dark energy allows similar, albeit less predictive, considerations. We discuss the cosmological finetuning
dS/CFT and spacetime topology
"... In the general Euclidean formulation of the AdS/CFT correspondence put forth in [25], one considers Riemannian manifolds of the form M n+1 × Y, where M n+1 is conformally compactifiable with conformal boundaryatinfinity N n. It is then a problem of fundamental interest to determine, ..."
Abstract

Cited by 31 (10 self)
 Add to MetaCart
In the general Euclidean formulation of the AdS/CFT correspondence put forth in [25], one considers Riemannian manifolds of the form M n+1 × Y, where M n+1 is conformally compactifiable with conformal boundaryatinfinity N n. It is then a problem of fundamental interest to determine,
Exploring de Sitter Space and Holography
, 2002
"... We explore aspects of the physics of de Sitter (dS) space that are relevant to holography with a positive cosmological constant. First we display a nonlocal map that commutes with the de Sitter isometries, transforms the bulkboundary propagator and solutions of free wave equations in de Sitter onto ..."
Abstract

Cited by 29 (2 self)
 Add to MetaCart
We explore aspects of the physics of de Sitter (dS) space that are relevant to holography with a positive cosmological constant. First we display a nonlocal map that commutes with the de Sitter isometries, transforms the bulkboundary propagator and solutions of free wave equations in de Sitter onto the same quantities in Euclidean antide Sitter (EAdS), and takes the two boundaries of dS to the single EAdS boundary via an antipodal identification. Second we compute the action of scalar fields on dS as a functional of boundary data. Third, we display a family of solutions to 3d gravity with a positive cosmological constant in which the equal time sections are arbitrary genus Riemann surfaces, and compute the action of these spaces as a functional of boundary data from the Einstein gravity and ChernSimons gravity points of view. These studies suggest that if de Sitter space is dual to a Euclidean conformal field theory (CFT), this theory should involve two disjoint, but possibly entangled factors. We argue that these CFTs would be of a novel form, with unusual hermiticity conditions relating left movers and right movers. After exploring these conditions in a toy model, we combine our observations to propose that a holographic dual description of de Sitter space would involve a pure entangled state in a product of two of our unconventional CFTs associated with the de Sitter boundaries. This state can be constructed to preserve the de Sitter symmetries and and its decomposition in a basis appropriate to antipodal inertial observers would lead to the thermal properties of static patch.
Composite Sbrane solutions related to Todatype systems
 Class. Quant. Grav.20
"... Composite Sbrane solutions in multidimensional gravity with scalar fields and fields of forms related to Todalike systems are presented. These solutions are defined on a product manifold R ∗ ×M1 ×... × Mn, where R ∗ is a time manifold, M1 is an Einstein manifold and Mi ( i> 1) are Ricciflat ma ..."
Abstract

Cited by 28 (19 self)
 Add to MetaCart
(Show Context)
Composite Sbrane solutions in multidimensional gravity with scalar fields and fields of forms related to Todalike systems are presented. These solutions are defined on a product manifold R ∗ ×M1 ×... × Mn, where R ∗ is a time manifold, M1 is an Einstein manifold and Mi ( i> 1) are Ricciflat manifolds. Certain examples of Sbrane solutions related to A1 +... + A1, Am Toda chains and those with ”blockorthogonal ” intersections (e.g. SMbrane solutions) are singled out. Under certain restrictions imposed a Kasnerlike asymptotical behaviour of the solutions is shown.
Micromanaging de Sitter holography
, 2010
"... We develop tools to engineer de Sitter vacua with semiholographic duals, using elliptic fibrations and orientifolds to uplift FreundRubin compactifications with CFT duals. The dual brane construction is compact and constitutes a microscopic realization of the dS/dS correspondence, realizing ddime ..."
Abstract

Cited by 24 (7 self)
 Add to MetaCart
(Show Context)
We develop tools to engineer de Sitter vacua with semiholographic duals, using elliptic fibrations and orientifolds to uplift FreundRubin compactifications with CFT duals. The dual brane construction is compact and constitutes a microscopic realization of the dS/dS correspondence, realizing ddimensional de Sitter space as a warped compactification down to (d − 1)dimensional de Sitter gravity coupled to a pair of largeN matter sectors. This provides a parametric microscopic interpretation of the GibbonsHawking entropy. We illustrate these ideas with an explicit class of