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49
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 ..."
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Cited by 125 (7 self)
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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
Modern tests of Lorentz invariance
 Living Rev. Rel
"... Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has gone into testing Lorentz invariance in various regimes. This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made such high precisio ..."
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Cited by 55 (1 self)
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Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has gone into testing Lorentz invariance in various regimes. This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made such high precision tests possible. The current constraints on Lorentz violating effects from both terrestrial experiments and astrophysical observations are presented.
Are Inflationary Predictions Sensitive to Very High Energy
 Physics?, J. High Energy Phys
"... Abstract: It has been proposed that the successful inflationary description of density perturbations on cosmological scales is sensitive to the details of physics at extremely high (transPlanckian) energies. We test this proposal by examining how inflationary predictions depend on higherenergy sca ..."
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Cited by 35 (9 self)
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Abstract: It has been proposed that the successful inflationary description of density perturbations on cosmological scales is sensitive to the details of physics at extremely high (transPlanckian) energies. We test this proposal by examining how inflationary predictions depend on higherenergy scales within a simple model where the higherenergy physics is well understood. We find the best of all possible worlds: inflationary predictions are robust against the vast majority of highenergy effects, but can be sensitive to some effects in certain circumstances, in a way which does not violate ordinary notions of decoupling. This implies both that the comparison of inflationary predictions with CMB data is meaningful, and that it is also worth searching for small deviations from the standard results in the
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 ..."
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Cited by 34 (8 self)
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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
Monodromy in the CMB: Gravity waves and string inflation,” arXiv:0803.3085 [hepth]; – 71
 J. High Energy Phys
"... We present a simple mechanism for obtaining largefield inflation, and hence a gravitational wave signature, from string theory compactified on twisted tori. For Nil manifolds, we obtain a leading inflationary potential proportional to φ 2/3 in terms of the canonically normalized field φ, yielding p ..."
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Cited by 20 (1 self)
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We present a simple mechanism for obtaining largefield inflation, and hence a gravitational wave signature, from string theory compactified on twisted tori. For Nil manifolds, we obtain a leading inflationary potential proportional to φ 2/3 in terms of the canonically normalized field φ, yielding predictions for the tilt of the power spectrum and the tensortoscalar ratio, ns ≈ 0.98 and r ≈ 0.04 with 60 efoldings of inflation; we note also the possibility of a variant with a candidate inflaton potential proportional to φ 2/5. The basic mechanism involved in extending the field range – monodromy in Dbranes as they move in circles on the manifold – arises in a more general class of compactifications, though our methods for controlling the
On the consistency of de Sitter vacua
 JHEP 0212 (2002) 025 [arXiv:hepth/0210058
"... In this paper the consistency of the de Sitter invariant αvacua, which have been introduced as simple tools to study the effects of transplanckian physics, is investigated. In particular possible non renormalization problems are discussed, as well as non standard properties of Greens functions. We ..."
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Cited by 11 (5 self)
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In this paper the consistency of the de Sitter invariant αvacua, which have been introduced as simple tools to study the effects of transplanckian physics, is investigated. In particular possible non renormalization problems are discussed, as well as non standard properties of Greens functions. We also discuss the non thermal properties of the αvacua and the necessity of α to change. The conclusion is that non of these problems necessarily exclude an application of the αvacua to inflation. The main driving force behind recent work on transplanckian physics in cosmology, is to find out whether physics beyond the Planck scale can give effects on the CMBR spectrum, [130]. A crucial ingredient in inflationary cosmology is that microscopic quantum fluctuations are magnified by inflation into macroscopic seeds for galaxy
Inflationary perturbations from deformed CFT
"... Abstract: We present a new method to calculate the spectrum of (slowroll) inflationary perturbations, inspired by the conjectured dS/CFT correspondence. We show how the standard result for the spectrum of inflationary perturbations can be obtained from deformed CFT correlators, whose behavior is de ..."
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Cited by 5 (2 self)
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Abstract: We present a new method to calculate the spectrum of (slowroll) inflationary perturbations, inspired by the conjectured dS/CFT correspondence. We show how the standard result for the spectrum of inflationary perturbations can be obtained from deformed CFT correlators, whose behavior is determined by the CallanSymanzik equation. We discuss the possible advantages of this approach and end with some comments on the role of holography in dS/CFT and its relation to the universal nature of the spectrum of inflationary perturbations.
QuasiSingle Field Inflation with Large Mass
"... We study the effect of massive isocurvaton on density perturbations in quasisingle field inflation models, when the mass of the isocurvaton M becomes larger than the order of the Hubble parameter H. We analytically compute the correction to the power spectrum, leading order in coupling but exact fo ..."
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Cited by 2 (0 self)
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We study the effect of massive isocurvaton on density perturbations in quasisingle field inflation models, when the mass of the isocurvaton M becomes larger than the order of the Hubble parameter H. We analytically compute the correction to the power spectrum, leading order in coupling but exact for all values of mass. This verifies the previous numerical results for the range 0 < M < 3H/2 and shows that, in the large mass limit, the correction is of order H2/M2. ar X iv
Do we have a Theory of Early Universe Cosmology?
"... The inflationary scenario has become the paradigm of early universe cosmology, and in conjuction with ideas from superstring theory has led to speculations about an “inflationary multiverse”. From a point of view of phenomenology, the inflationary universe scenario has been very successful. Howev ..."
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Cited by 2 (0 self)
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The inflationary scenario has become the paradigm of early universe cosmology, and in conjuction with ideas from superstring theory has led to speculations about an “inflationary multiverse”. From a point of view of phenomenology, the inflationary universe scenario has been very successful. However, the scenario suffers from some conceptual problems, and thus it does not (yet) have the status of a solid theory. There are alternative ideas for the evolution of the very early universe which do not involve inflation but which agree with most current cosmological observations as well as inflation does. In this lecture I will outline the conceptual problems of inflation and introduce two alternative pictures the “matter bounce ” and “string gas cosmology”, the latter being a realization of the “emergent universe ” scenario based on some key principles of superstring theory. I will demonstrate that these two alternative pictures lead to the same predictions for the power spectrum of the observed largescale structure and for the angular power spectrum of cosmic microwave background anisotropies as the inflationary scenario, and I will mention predictions for future observations with which the three scenarios can be observationally teased apart. Keywords: