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Related papers: Steady-State Eternal Inflation

200 papers

We consider the eternal inflation scenario of the slow-roll/chaotic type with the additional element of an objective collapse of the wave function. The incorporation of this new agent to the traditional inflationary setting might represent…

General Relativity and Quantum Cosmology · Physics 2017-10-27 Gabriel Leon

Inflationary models, especially those with plateau-type potentials, are consistent with the cosmological data, but inflation itself does not resolve the initial singularity. This singularity is resolved, for example, by the idea of the…

General Relativity and Quantum Cosmology · Physics 2024-05-16 Hiroki Matsui , Alexandros Papageorgiou , Fuminobu Takahashi , Takahiro Terada

We show why the universe started in an unstable de Sitter state. The quantum origin of our universe implies one must take a `top down' approach to the problem of initial conditions in cosmology, in which the histories that contribute to the…

High Energy Physics - Theory · Physics 2009-11-07 S. W. Hawking , Thomas Hertog

It is shown that a physically reasonable spacetime that is eternally inflating to the future must possess an initial singularity.

General Relativity and Quantum Cosmology · Physics 2010-04-06 Arvind Borde , Alexander Vilenkin

An outgrowth of the idea of inflation is advanced. In the inflation regime, the singularity condition is broken. Equations which govern inflation are invariant under time reversal, so that they describe deflation as well. Those two…

General Physics · Physics 2009-11-02 Vladimir S. Mashkevich

In this paper we introduce a simple discrete stochastic model of eternal inflation that shares many of the most important features of the continuum theory as it is now understood. The model allows us to construct a multiverse and rigorously…

High Energy Physics - Theory · Physics 2013-05-30 Daniel Harlow , Stephen Shenker , Douglas Stanford , Leonard Susskind

We construct analytic and numerical solutions of the Fokker-Planck equation that arises in the context of stochastic inflation. We use these solutions to derive necessary conditions for eternal inflation on the higher derivatives of the…

High Energy Physics - Theory · Physics 2019-08-14 Tom Rudelius

In a previous paper we proposed a new approach to the beginning of inflation -- a lingering universe. The universe begins in a lingering state with a nearly vanishing Hubble parameter. This calls into question the absolute age of the…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-09 Brandon Melcher , Arnab Pradhan , Scott Watson

We show that eternal inflation is compatible with holography. In particular, we emphasize that if a region is asymptotically de Sitter in the future, holographic arguments by themselves place no bound on the number of past e-foldings. We…

High Energy Physics - Theory · Physics 2009-11-10 David A. Lowe , Donald Marolf

In [1] a new cosmological model is proposed with no big bang singularity in the past, though past geodesically incomplete. This model starts with an inflationary era, follows with a stiff matter dominated period and evolves to accelerated…

General Relativity and Quantum Cosmology · Physics 2016-08-09 L. Fernandez-Jambrina

The basic workings of inflationary models are summarized, along with the arguments that strongly suggest that our universe is the product of inflation. The mechanisms that lead to eternal inflation in both new and chaotic models are…

Astrophysics · Physics 2009-10-31 Alan H. Guth

We provide a realisation of a singularity-free inflationary universe in the form of a simple cosmological model dominated at early times by a single minimally coupled scalar field with a physically based potential. The universe starts…

General Relativity and Quantum Cosmology · Physics 2008-11-26 George F. R. Ellis , Jeff Murugan , Christos G. Tsagas

Many inflating spacetimes are likely to violate the weak energy condition, a key assumption of singularity theorems. Here we offer a simple kinematical argument, requiring no energy condition, that a cosmological model which is inflating --…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Arvind Borde , Alan H. Guth , Alexander Vilenkin

The solution for an inflationary universe without singularities is derived from the Einstein-Lemaitre equations. The present state of the universe evolved from a steady state solution for a tiny, but classical micro-universe with large…

Astrophysics · Physics 2007-05-23 E. Rebhan

In hep-th/0506040 we discussed a classically constrained model of gravity. This theory contains known solutions of General Relativity (GR), and admits solutions that are absent in GR. Here we study cosmological implications of some of these…

High Energy Physics - Theory · Physics 2008-11-26 Gregory Gabadadze , Yanwen Shang

The eternal inflation problem continues to be considered one of standard's cosmology most serious shortcomings. This arises when one considers the effects of "quantum fluctuations" (QF) on the zero mode of inflaton field during a Hubble…

General Relativity and Quantum Cosmology · Physics 2023-11-22 R. L. Lechuga , D. Sudarsky

We discuss cosmological models for an eternal universe. Physical observables show no singularity from the infinite past to the infinite future. While the universe is evolving, there is no beginning and no end - the universe exists forever.…

General Relativity and Quantum Cosmology · Physics 2014-08-27 C. Wetterich

Inflation is the currently accepted paradigm for the beginnings of the Universe. To explain the observed almost scale invariant spectrum of density perturbations with only a slight spectral tilt, inflation must have been "slow roll", that…

High Energy Physics - Theory · Physics 2021-01-07 Hao Geng

It has recently been realized that many theories of physics beyond the Standard Model give rise to cosmological histories exhibiting extended epochs of cosmological stasis. During such epochs, the abundances of different energy components…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-17 Keith R. Dienes , Lucien Heurtier , Fei Huang , Tim M. P. Tait , Brooks Thomas

We investigate the condition for eternal inflation to take place in the noncommutative spacetime. We find that the possibility for eternal inflation's happening is greatly suppressed in this case. If eternal inflation cannot happen in the…

High Energy Physics - Theory · Physics 2010-10-27 Yi-Fu Cai , Yi Wang