Andrei Linde
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View article: Post-inflationary enhancement of adiabatic perturbations in modular cosmology
Post-inflationary enhancement of adiabatic perturbations in modular cosmology Open
We show that multi-field inflationary models with negligible turning in field space during inflation can lead to an effective sourcing of adiabatic from entropic perturbations after the end of inflation. We illustrate this general phenomen…
View article: The BAO-CMB Tension and Implications for Inflation
The BAO-CMB Tension and Implications for Inflation Open
The scalar spectral index $n_s$ is a powerful test of inflationary models. The tightest constraint on $n_s$ to date derives from the combination of cosmic microwave background (CMB) data with baryon acoustic oscillation (BAO) data. The res…
View article: Post-inflationary enhancement of adiabatic perturbations in modular cosmology
Post-inflationary enhancement of adiabatic perturbations in modular cosmology Open
We show that multi-field inflationary models with negligible turning in field space during inflation can lead to an effective sourcing of adiabatic from entropic perturbations {\it after} the end of inflation. We illustrate this general ph…
View article: On the Present Status of Inflationary Cosmology
On the Present Status of Inflationary Cosmology Open
We give a brief review of the basic principles of inflationary theory and discuss the present status of the simplest inflationary models that can describe Planck/BICEP/Keck observational data by choice of a single model parameter. In parti…
View article: ACT, SPT, and chaotic inflation
ACT, SPT, and chaotic inflation Open
We show that the simplest generalization of the chaotic inflation model $\tfrac12 {m^{2}ϕ^{2}}$ with nonminimal coupling to gravity $(1+ϕ) R$ provides a good match to the results of the latest data release of the Atacama Cosmology Telescop…
View article: Axion Stabilization in Modular Cosmology
Axion Stabilization in Modular Cosmology Open
The $SL(2,\mathbb{Z})$ invariant $α$-attractor models have plateau potentials with respect to the inflaton and axion fields. The potential in the axion direction is almost exactly flat during inflation, hence, the axion field remains nearl…
View article: Double Exponents in $SL(2,\mathbb{Z})$ Cosmology
Double Exponents in $SL(2,\mathbb{Z})$ Cosmology Open
Recently proposed $SL(2,\mathbb{Z})$ invariant $α$-attractor models have plateau potentials with respect to the inflaton and axion fields. The slope of the potential in the inflaton direction is exponentially suppressed at large values of …
View article: Landscape of Modular Cosmology
Landscape of Modular Cosmology Open
We investigate the global structure of the recently discovered family of $SL(2,\mathbb{Z})$-invariant potentials describing inflationary $α$-attractors. These potentials have an inflationary plateau consisting of the fundamental domain and…
View article: $SL(2,\mathbb{Z})$ Cosmological Attractors
$SL(2,\mathbb{Z})$ Cosmological Attractors Open
We study cosmological theory where the kinetic term and potential have $SL(2,\mathbb{Z})$ symmetry. Potentials have a plateau at large values of the inflaton field, where the axion forms a flat direction. Due to the underlying hyperbolic g…
View article: Hybrid $α$-attractors, primordial black holes and gravitational wave backgrounds
Hybrid $α$-attractors, primordial black holes and gravitational wave backgrounds Open
We investigate the two-stage inflation regime in the theory of hybrid cosmological $α$-attractors. The spectrum of inflationary perturbations is compatible with the latest Planck/BICEP/Keck results, thanks to the attractor properties of th…
View article: Goldstino condensation?
Goldstino condensation? Open
A bstract It was argued in [1] that the Volkov-Akulov (VA) model as well as similar models in supergravity and the related KKLT model in string theory, suffer from tachyonic instabilities due to goldstino condensation. The authors of [1] c…
View article: Dilaton-axion inflation with PBHs and GWs
Dilaton-axion inflation with PBHs and GWs Open
We discuss two-stage dilaton-axion inflation models [1] and describe α -attractor models with either exponential or polynomial approach to the plateau. We implement one of the models of primordial black hole production proposed in [2] in t…
View article: Hybrid cosmological attractors
Hybrid cosmological attractors Open
We construct $\\alpha$-attractor versions of hybrid inflation models. In these\nmodels, the potential of the inflaton field $\\varphi$ is uplifted by the\npotential of the second field $\\chi$. This uplifting ends due to a tachyonic\ninsta…
View article: Polynomial α-attractors
Polynomial α-attractors Open
Inflationary α -attractor models can be naturally implemented in supergravity with hyperbolic geometry. They have stable predictions for observables, such as n s = 1 - 2/ N e , assuming that the potential in terms of the original geometric…
View article: BICEP/Keck and cosmological attractors
BICEP/Keck and cosmological attractors Open
We discuss implications of the latest BICEP/Keck data release for inflationary models, with special emphasis on the cosmological attractors which can describe all presently available inflation-related observational data. These models are c…
View article: Sequestered Inflation
Sequestered Inflation Open
We construct supergravity models allowing to sequester the phenomenology of inflation from the Planckian energy scale physics. The procedure consists of two steps: At Step I we study supergravity models, which might be associated with stri…
View article: de Sitter minima from M-theory and string theory
de Sitter minima from M-theory and string theory Open
We study M-theory compactification on ${\\mathbb{T}^7/ \\mathbb{Z}_2^3}$ in the\npresence of a seven-flux, metric fluxes and KK monopoles. The effective\nfour-dimensional supergravity has seven chiral multiplets whose couplings are\nspecif…
View article: CMB targets after the latest <i>Planck</i> data release
CMB targets after the latest <i>Planck</i> data release Open
We show that a combination of the simplest $\alpha$-attractors and KKLTI models related to Dp-brane inflation covers most of the area in the ($n_{s}$, $r$) space favored by Planck 2018. For $\alpha$-attractor models, there are discrete tar…
View article: dS vacua and the swampland
dS vacua and the swampland Open
A bstract In this note we revisit some of the recent 10d and 4d arguments suggesting that the uplifting of supersymmetric AdS vacua leads to a flattening of the potential, preventing the formation of dS vacua. We explain why the correspond…
View article: 4D models of de Sitter uplift
4D models of de Sitter uplift Open
It was shown in arXiv:1808.09428 that the modified 4d version of the KKLT\nmodel proposed in arXiv:1707.08678 is inconsistent for large values of the\nparameter $c$ advocated in arXiv:1707.08678, since there is a point in the\nmoduli space…
View article: Planck 2018 and brane inflation revisited
Planck 2018 and brane inflation revisited Open
A bstract We revisit phenomenological as well as string-theoretical aspects of D-brane inflation cosmological models. Phenomenologically these models stand out on par with α -attractors, as models with Planck-compatible values of n s , mov…
View article: Reverse Engineering the Universe
Reverse Engineering the Universe Open
We describe the basic principles of inflationary cosmology and explain how it may help to create the universe, or maybe even the multiverse, from less than one milligram of matter. We review the recent observational evidence supporting thi…
View article: The Landscape, the Swampland and the Era of Precision Cosmology
The Landscape, the Swampland and the Era of Precision Cosmology Open
We review the advanced version of the KKLT construction and pure de Sitter supergravity, involving a nilpotent multiplet, with regard to various conjectures that de Sitter state cannot exist in string theory. We explain why we consider the…
View article: de Sitter Vacua with a Nilpotent Superfield
de Sitter Vacua with a Nilpotent Superfield Open
We study the arguments given in [ ] which suggest that the uplifting procedure in the KKLT construction is not valid. First we show that the modification of the SUSY breaking sector of the nilpotent superfield, as proposed in [ ], is not c…
View article: Hypernatural inflation
Hypernatural inflation Open
We constructed a model of natural inflation in the context of\n$\\alpha$-attractor supergravity, in which both the dilaton field and the axion\nfield are light during inflation, and the inflaton may be a combination of the\ntwo. The T-mode…
View article: Large field inflation: Recent progress and observational predictions
Large field inflation: Recent progress and observational predictions Open
I will describe the new generation of inflationary models with plateau potentials and their
\nobservational predictions. I will also discuss the problem of initial conditions for inflation in
\nsuch models.