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Related papers: No-boundary extremal surfaces in slow-roll inflati…

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We study no-boundary de Sitter extremal surfaces and their pseudo-entropy areas for generic subregions at the future boundary, building on previous work. For large subregions, timelike+Euclidean extremal surfaces exist with transparent…

High Energy Physics - Theory · Physics 2026-04-02 K. Narayan

We study extremal surfaces in de Sitter space in the Poincare slicing in the upper patch, anchored on spatial subregions at the future boundary ${\cal I}^+$, restricted to constant boundary Euclidean time slices (focussing on strip…

High Energy Physics - Theory · Physics 2015-06-24 K. Narayan

We develop further the investigations in arXiv:2210.12963 [hep-th] on de Sitter space, extremal surfaces and time entanglement. We discuss the no-boundary de Sitter extremal surface areas as certain analytic continuations from $AdS$ while…

High Energy Physics - Theory · Physics 2025-03-03 K. Narayan

Following arXiv:1501.03019 [hep-th], we study de Sitter space and spherical subregions on a constant boundary Euclidean time slice of the future boundary in the Poincare slicing. We show that as in that case, complex extremal surfaces exist…

High Energy Physics - Theory · Physics 2015-12-23 K. Narayan

We develop our recent suggestion that inflation may be made past eternal, so that there is no initial cosmological singularity or "beginning of time". Inflation with multiple vacua generically approaches a steady-state statistical…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Anthony Aguirre , Steven Gratton

We study extremal surfaces in the static patch coordinatization of de Sitter space, focussing on the future and past universes. We find connected timelike codim-2 surfaces on a boundary Euclidean time slice stretching from the future…

High Energy Physics - Theory · Physics 2018-07-10 K. Narayan

We develop further previous work on de Sitter extremal surfaces and time entanglement structures in quantum mechanics. In the first part, we first discuss explicit quotient geometries. Then we construct smooth bulk geometries with replica…

High Energy Physics - Theory · Physics 2025-11-20 Kanhu Kishore Nanda , K. Narayan , Somnath Porey , Gopal Yadav

We refine previous investigations on de Sitter space and extremal surfaces anchored at the future boundary $I^+$. Since such surfaces do not return, they require extra data or boundary conditions in the past (interior). In entirely…

High Energy Physics - Theory · Physics 2023-06-21 K. Narayan

We review aspects of the Hartle-Hawking no boundary geometry in the context of slow roll inflation. We give an analytic approximation to the geometry and we explain the rationale for the proposal. We also explain why it gives a prediction…

High Energy Physics - Theory · Physics 2024-10-04 Juan Maldacena

It has recently been shown that in single field slow-roll inflation the total volume cannot grow by a factor larger than e^(S_dS/2) without becoming infinite. The bound is saturated exactly at the phase transition to eternal inflation where…

High Energy Physics - Theory · Physics 2015-06-03 Sergei Dubovsky , Leonardo Senatore , Giovanni Villadoro

We show that in any model of non-eternal inflation satisfying the null energy condition, the area of the de Sitter horizon increases by at least one Planck unit in each inflationary e-folding. This observation gives an operational meaning…

High Energy Physics - Theory · Physics 2009-11-13 Nima Arkani-Hamed , Sergei Dubovsky , Alberto Nicolis , Enrico Trincherini , Giovanni Villadoro

We study extremal surfaces in the Schwarzschild de Sitter spacetime with real mass parameter. We find codim-2 timelike extremal surfaces stretching between the future and past boundaries that pass through the vicinity of the cosmological…

High Energy Physics - Theory · Physics 2020-10-28 Karan Fernandes , Kedar S. Kolekar , K. Narayan , Sourav Roy

The evolution of slow--roll inflation in a five--dimensional brane world model with two boundary branes and bulk scalar field is studied. Assuming that the inflationary scale is below the brane tension, we can employ the moduli space…

Astrophysics · Physics 2009-11-10 P. R. Ashcroft , C. van de Bruck , A. -C. Davis

Non-trivial inflaton self-interactions can yield calculable signatures of primordial non-Gaussianity that are measurable in cosmic surveys. Surprisingly, we find that the phase transition to slow-roll eternal inflation is often incalculable…

High Energy Physics - Theory · Physics 2023-05-10 Timothy Cohen , Daniel Green , Akhil Premkumar

For spaces which are not asymptotically anti-de Sitter where the asymptotic behavior is deformed by replacing the cosmological constant by a dilaton scalar potential, we show that it is possible to have well-defined boundary stress-energy…

High Energy Physics - Theory · Physics 2009-10-31 Rong-Gen Cai , Nobuyoshi Ohta

An introductory, self-contained overview, with pedagogical figures, is provided to acquaint readers unfamiliar with the subjects with key aspects of de Sitter space and inflation. The connection between de Sitter space and cosmology is…

General Relativity and Quantum Cosmology · Physics 2025-10-30 Eyad H. Al-Samra

We consider the no-boundary proposal for homogeneous isotropic closed universes with a cosmological constant and a scalar field with a quadratic potential. In the semi-classical limit, it predicts classical behavior at late times if the…

High Energy Physics - Theory · Physics 2008-11-26 James B. Hartle , S. W. Hawking , Thomas Hertog

Following arXiv:2012.07351 [hep-th], we study quantum extremal surfaces in various families of cosmologies with Big-Crunch singularities, by extremizing the generalized entropy in 2-dimensional backgrounds which can be thought of as arising…

High Energy Physics - Theory · Physics 2022-04-20 Kaberi Goswami , K. Narayan , Hitesh K. Saini

We consider the quasi-de Sitter geometry of the inflationary universe. We calculate the energy flux of the slowly rolling background scalar field through the quasi-de Sitter apparent horizon and set it equal to the change of the entropy…

High Energy Physics - Theory · Physics 2009-11-07 Andrei Frolov , Lev Kofman

We present a new inflation model, known as noncommutative decrumpling inflation, in which space has noncommutative geometry with time variability of the number of spatial dimensions. Within the framework of noncommutative decrumpling…

High Energy Physics - Theory · Physics 2009-11-10 Forough Nasseri , S. A. Alavi
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