English
Related papers

Related papers: Algebraic Observational Cosmology

200 papers

We study the von Neumann algebra description of the inflationary quasi-de Sitter (dS) space. Unlike perfect dS space, quasi-dS space allows the nonzero energy flux across the horizon, which can be identified with the expectation value of…

High Energy Physics - Theory · Physics 2023-11-08 Min-Seok Seo

We describe an algebra of observables for a static patch in de Sitter space, with operators gravitationally dressed to the worldline of an observer. The algebra is a von Neumann algebra of Type II$_1$. There is a natural notion of entropy…

High Energy Physics - Theory · Physics 2023-07-04 Venkatesa Chandrasekaran , Roberto Longo , Geoff Penington , Edward Witten

Cosmic inflation provides a window to the highest energy densities accessible in nature, far beyond those achievable in any realistic terrestrial experiment. Theoretical insights into the inflationary era and its observational probes may…

There has been much recent interest in the necessity of an observer degree of freedom in the description of local algebras in semiclassical gravity. In this work, we describe an example where the observer can be constructed intrinsically…

High Energy Physics - Theory · Physics 2025-04-11 Antony J. Speranza

In a universe dominated by a small cosmological constant or by eternal dark energy with equation of state w < -1/3, observers are surrounded by event horizons. The horizons limit how much of the universe the observers can ever access. We…

Astrophysics · Physics 2009-11-10 Nemanja Kaloper , Matthew Kleban , Lorenzo Sorbo

We study the algebra of observables in semiclassical quantum gravity for cosmological backgrounds, focusing on two key examples: slow-roll inflation and evaporating Schwarzschild-de Sitter black holes. In both cases, we demonstrate the…

High Energy Physics - Theory · Physics 2024-06-06 Chang-Han Chen , Geoff Penington

We argue that the total observable entropy is bounded by the inverse of the cosmological constant. This holds for all space-times with a positive cosmological constant, including cosmologies dominated by ordinary matter, and recollapsing…

High Energy Physics - Theory · Physics 2009-10-31 Raphael Bousso

We propose a model for cosmic inflation which is based on an effective description of strongly interacting, nonsupersymmetric matter within the framework of dynamical Abelian projection and centerization. The underlying gauge symmetry is…

High Energy Physics - Phenomenology · Physics 2009-11-07 Ralf Hofmann , Mathias Th. Keil

We consider the algebra of observables of perturbative quantum gravity in the exterior of a stationary black hole or the static patch of de Sitter spacetime. It was previously argued that the backreaction of gravitons on the spacetime…

High Energy Physics - Theory · Physics 2026-01-14 Marc S. Klinger , Jonah Kudler-Flam , Gautam Satishchandran

We study a scalar-tensor cosmological model where the Einstein tensor is non-minimally coupled to the free scalar field dynamics. Using FRW metric, we investigate the behavior of scale factor for vacuum, matter and dark energy dominated…

General Relativity and Quantum Cosmology · Physics 2015-08-06 F. Darabi , A. Parsiya

We study a class of non-local, action-based, and purely gravitational models. These models seek to describe a cosmology in which inflation is driven by a large, bare cosmological constant that is screened by the self-gravitation between the…

General Relativity and Quantum Cosmology · Physics 2016-08-17 N. C. Tsamis , R. P. Woodard

Using the dS/QFT correspondence in the context of inflation allows for the study of interesting, otherwise inaccessible physics. In particular, by studying inflation via its dual field theory at the boundary of the de Sitter space, it may…

Cosmology and Nongalactic Astrophysics · Physics 2011-08-08 Mafalda Dias

We propose a model for cosmic inflation which is based on an effective description of strongly interacting, nonsupersymmetric matter within the framework of dynamical abelian projection and centerization. The underlying gauge symmetry is…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ralf Hofmann , Mathias Th. Keil

We consider quantum algebras of observables associated with subregions in theories of Einstein gravity coupled to matter in the $G_N\rightarrow 0$ limit. When the subregion is spatially compact or encompasses an asymptotic boundary, we…

High Energy Physics - Theory · Physics 2024-02-07 Kristan Jensen , Jonathan Sorce , Antony Speranza

Alan Guth introduced cosmologists to inflation at the 1980 Texas Symposium. Since, inflation has had almost as much impact on cosmology as the big-bang model itself. However, unlike the big-bang model, it has little observational support.…

Astrophysics · Physics 2014-10-13 Michael S. Turner

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

The notion of inflation (past or present) in standard cosmological models is shown to be a consequence of a sufficiently high second law entropy production from the internal heating of the universal expansion. The longitudinal viscous…

General Relativity and Quantum Cosmology · Physics 2007-05-23 T. Sakai , A. Widom , Y. N. Srivastava

In this dissertation, we introduce a general way of modeling inflation in a framework that is independent of the exact nature of the inflationary potential. Because of the choice of our initial conditions and the continuity of the scale…

High Energy Physics - Theory · Physics 2009-05-19 Matthew M. Glenz

Primordial fluctuations in inflationary cosmology acquire classical properties through decoherence when their wavelengths become larger than the Hubble scale. Although decoherence is effective, it is not complete, so a significant part of…

Astrophysics · Physics 2008-11-26 C. Kiefer , I. Lohmar , D. Polarski , A. A. Starobinsky

We are on the verge of the first precision testing of the inflationary cosmology as a model for the origin of structure in the Universe. I review the key predictions of inflation which can be used as observational tests, in the sense of…

Astrophysics · Physics 2007-05-23 Andrew R Liddle
‹ Prev 1 2 3 10 Next ›