Results 1  10
of
21
Raamsdonk, Rindler Quantum Gravity
"... In this note, we explain how asymptotically globally AdS spacetimes can be given an alternate dual description as entangled states of a pair of hyperbolic space CFTs, which are associated with complementary Rindler wedges of the AdS geometry. The reduced density matrix encoding the state of the degr ..."
Abstract

Cited by 10 (1 self)
 Add to MetaCart
(Show Context)
In this note, we explain how asymptotically globally AdS spacetimes can be given an alternate dual description as entangled states of a pair of hyperbolic space CFTs, which are associated with complementary Rindler wedges of the AdS geometry. The reduced density matrix encoding the state of the degrees of freedom in one of these CFTs describes the physics in a single wedge, which we can think of as the region of spacetime accessible to an accelerated observer in AdS. For pure AdS, this density matrix is thermal, and we argue that the microstates in this thermal ensemble correspond to spacetimes that are almost indistinguishable from a Rindler wedge of pure AdS away from the horizon, but with the horizon replaced by some kind of singularity where the geometrical description breaks down. This alternate description of AdS, based on patches associated with particular observers, may give insight into the holographic description of cosmologies where no observer has access to the full spacetime. ar
Higher Spin de Sitter Holography from Functional Determinants
, 2013
"... We discuss further aspects of the higher spin dS/CFT correspondence. Using a recent result of Dunne and Kirsten, it is shown how to numerically compute the partition function of the free Sp(N) model for a large class of SO(3) preserving deformations of the flat/round metric on R3/S3 and the source o ..."
Abstract

Cited by 10 (2 self)
 Add to MetaCart
(Show Context)
We discuss further aspects of the higher spin dS/CFT correspondence. Using a recent result of Dunne and Kirsten, it is shown how to numerically compute the partition function of the free Sp(N) model for a large class of SO(3) preserving deformations of the flat/round metric on R3/S3 and the source of the spinzero singletrace operator dual to the bulk scalar. We interpret this partition function as a HartleHawking wavefunctional. It has a local maximum about the pure de Sitter vacuum. Restricting to SO(3) preserving deformations, other local maxima (which exceed the one near the de Sitter vacuum) can peak at inhomogeneous and anisotropic values of the late time metric and scalar profile. Numerical experiments suggest the remarkable observation that, upon fixing a certain average of the bulk scalar profile at I+, the wavefunction becomes normalizable in all the other (infinite) directions of the deformation. We elucidate the meaning of double trace deformations in the context of dS/CFT as a change of basis and as a convolution. Finally, we discuss possible extensions of higher spin de Sitter holography by coupling the free theory to a ChernSimons term.
Perturbative Critical Behavior from Spacetime Dependent Couplings
"... We find novel perturbative fixed points by introducing mildly spacetimedependent couplings into otherwise marginal terms. In fourdimensional QFT, these are physical analogues of the smallǫ WilsonFisher fixed point. Rather than considering 4 − ǫ dimensions, we stay in four dimensions but introduc ..."
Abstract

Cited by 8 (4 self)
 Add to MetaCart
(Show Context)
We find novel perturbative fixed points by introducing mildly spacetimedependent couplings into otherwise marginal terms. In fourdimensional QFT, these are physical analogues of the smallǫ WilsonFisher fixed point. Rather than considering 4 − ǫ dimensions, we stay in four dimensions but introduce couplings whose leading spacetime dependence is of the form λxκµκ, with a small parameter κ playing a role analogous to ǫ. We show, in φ4 theory and in QED and QCD with massless flavors, that this leads to a critical theory under perturbative control over an exponentially wide window of spacetime positions x. The exact fixed point coupling λ∗(x) in our theory is identical to the running coupling of the translationally invariant theory, with the scale replaced by 1/x. Similar statements hold for threedimensional φ6 theories and twodimensional sigma models with curved target spaces. We also describe strongly coupled examples using conformal perturbation theory.
Les Houches lectures on inflationary observables and string theory,’’ arXiv:1311.2312 [hepth
"... These lectures cover the theoretical structure and phenomenology of some basic mechanisms for inflation. A full treatment of the problem requires ‘ultraviolet completion ’ because of the sensitivity of inflation to quantum gravity effects, while the observables are elegantly parameterized using low ..."
Abstract

Cited by 6 (0 self)
 Add to MetaCart
(Show Context)
These lectures cover the theoretical structure and phenomenology of some basic mechanisms for inflation. A full treatment of the problem requires ‘ultraviolet completion ’ because of the sensitivity of inflation to quantum gravity effects, while the observables are elegantly parameterized using low energy field theory. String theory provides novel mechanisms for inflation, some subject to significant observational tests, with highly UVsensitive tensor mode measurements being a prime example. Although the ultraviolet completion is not directly accessible experimentally, some of these mechanisms have helped stimulate a more systematic analysis of the space of low energy theories and signatures relevant for data analysis, including searches for nonGaussianity and additional structure in the power spectrum. We include a pedagogical overview of string compactifications, with a focus on candidate inflatons and their symmetry structure. In the last lecture we attack the problem of thoughtexperimental observables in inflation, developing a generalization of gaugegravity duality that relies on the structure of the scalar potential in string theory. ar X iv
De Sitter Musings
, 2013
"... We discuss some of the issues that arise when considering the physics of asymptotically de Sitter spacetimes, and attempts to address them. Our development begins at the classical level, where several initial value problems are discussed, and ends with several proposals for holography in asymptotica ..."
Abstract

Cited by 3 (0 self)
 Add to MetaCart
We discuss some of the issues that arise when considering the physics of asymptotically de Sitter spacetimes, and attempts to address them. Our development begins at the classical level, where several initial value problems are discussed, and ends with several proposals for holography in asymptotically de Sitter spacetimes. Throughout the paper we give a review of some basic notions such as the geometry of the Schwarzschildde Sitter black hole, the Nariai limit, and quantum field theory in a fixed de Sitter background. We also briefly discuss some semiclassical aspects such as the nucleation of giant black holes and the HartleHawking wavefunctional. We end by giving an overview of some open questions. An emphasis is placed on the differences between a static patch observer confined to live in a thermal cavity and the metaobserver who has access to a finite region of the future boundary.
Analytic Colemande Luccia Geometries
"... Abstract: We present the necessary and sufficient conditions for a Euclidean scale factor to be a solution of the Colemande Luccia equations for some analytic potential V (φ), with a Lorentzian continuation describing the growth of a bubble of lowerenergy vacuum surrounded by higherenergy vacuum. ..."
Abstract

Cited by 1 (1 self)
 Add to MetaCart
(Show Context)
Abstract: We present the necessary and sufficient conditions for a Euclidean scale factor to be a solution of the Colemande Luccia equations for some analytic potential V (φ), with a Lorentzian continuation describing the growth of a bubble of lowerenergy vacuum surrounded by higherenergy vacuum. We then give a set of explicit examples that satisfy the conditions and thus are closedform analytic examples of Colemande
The Powers of Monodromy
, 2014
"... Flux couplings to string theory axions yield superPlanckian field ranges along which the axion potential energy grows. At the same time, other aspects of the physics remain essentially unchanged along these large displacements, respecting a discrete shift symmetry with a subPlanckian period. Afte ..."
Abstract

Cited by 1 (1 self)
 Add to MetaCart
Flux couplings to string theory axions yield superPlanckian field ranges along which the axion potential energy grows. At the same time, other aspects of the physics remain essentially unchanged along these large displacements, respecting a discrete shift symmetry with a subPlanckian period. After a general overview of this monodromy effect and its application to largefield inflation, we present new classes of specific models of monodromy inflation, with monomial potentials µ4−pφp. A key simplification in these models is that the inflaton potential energy plays a leading role in moduli stabilization during inflation. The resulting inflatondependent shifts in the moduli fields lead to an effective flattening of the inflaton potential, i.e. a reduction of the exponent from a fiducial value p0 to p < p0. We focus on examples arising in compactifications of type IIB string theory on products of tori or Riemann surfaces, where the inflaton descends from the NSNS twoform potential B2, with monodromy induced by a coupling to the RR field strength F1. In this setting we exhibit models with p = 2/3, 4/3, 2, and 3, corresponding to predictions for the tensortoscalar ratio of r ≈ 0.04, 0.09, 0.13, and 0.2, respectively. Using mirror symmetry, we also motivate a second class of examples with the role of the axions played by the real parts of complex structure moduli, with fluxes inducing monodromy. ar X iv
Moduli Stabilization and the Holographic RG for AdS and dS
"... We relate moduli stabilization (V ′ = 0) in the bulk of AdSD or dSD to basic properties of the Wilsonian effective action in the holographic dual theory on dSD−1: the singletrace terms in the action have vanishing beta functions, and highertrace couplings are determined purely from lowertrace ..."
Abstract

Cited by 1 (0 self)
 Add to MetaCart
(Show Context)
We relate moduli stabilization (V ′ = 0) in the bulk of AdSD or dSD to basic properties of the Wilsonian effective action in the holographic dual theory on dSD−1: the singletrace terms in the action have vanishing beta functions, and highertrace couplings are determined purely from lowertrace ones. In the de Sitter case, this encodes the maximal symmetry of the bulk spacetime in a quantity which is accessible within an observer patch. Along the way, we clarify the role of counterterms, constraints, and operator redundancy in the Wilsonian holographic RG prescription, reproducing the expected behavior of the trace of the stressenergy tensor in the dual for both AdSD and dSD. We further show that metastability of the gravityside potential energy corresponds to a nonperturbatively small imaginary contribution to the Wilsonian action of pure de Sitter, a result consistent with the need for additional degrees of freedom in
SEE PROFILE
, 2016
"... A paucity of bulk entangling surfaces: AdS wormholes with de Sitter interiors ..."
Abstract
 Add to MetaCart
A paucity of bulk entangling surfaces: AdS wormholes with de Sitter interiors
Contents
"... We examine the late time behavior of the BunchDavies wavefunction for interacting light fields in a de Sitter background. We use perturbative techniques developed in the framework of AdS/CFT, and analytically continue to compute tree and loop level contributions to the BunchDavies wavefunction. We ..."
Abstract
 Add to MetaCart
We examine the late time behavior of the BunchDavies wavefunction for interacting light fields in a de Sitter background. We use perturbative techniques developed in the framework of AdS/CFT, and analytically continue to compute tree and loop level contributions to the BunchDavies wavefunction. We consider selfinteracting scalars of general mass, but focus especially on the massless and conformally coupled cases. We show that certain contributions grow logarithmically in conformal time both at tree and loop level. We also consider gauge fields and gravitons. The fourdimensional FeffermanGraham expansion of classical asymptotically de Sitter solutions is used to show that the wavefunction contains no logarithmic growth in the pure graviton sector at tree level. Finally, assuming a holographic relation between the wavefunction and the partition function of a conformal field theory, we interpret the logarithmic growths in the language of conformal field theory. ar X iv