English
Related papers

Related papers: Positive vacuum energy and the N-bound

200 papers

Current evidence suggests that the cosmological constant is not zero, or that we live in an open universe. We examine the implications for the future under these assumptions, and find that they are striking. If the Universe is cosmological…

Astrophysics · Physics 2009-10-31 Lawrence M. Krauss , Glenn D. Starkman

Recent observations of high-redshift supernovae seem to suggest that the global geometry of the Universe may be affected by a `cosmological constant', which acts to accelerate the expansion rate with time. But these data by themselves still…

Astrophysics · Physics 2009-10-31 Idit Zehavi , Avishai Dekel

In this paper we seek to understand what current knowledge of entanglement entropies suggests about the appropriate way to interpret the covariant entropy bound. We first begin by arguing that just as in the classical case, a universal…

History and Philosophy of Physics · Physics 2024-07-31 Emily Adlam

It is shown that topological changes in space-time are necessary to make General Relativity compatible with the Newtonian limit and to solve the hierarchy of the fundamental interactions. We detail how topology and topological changes…

General Relativity and Quantum Cosmology · Physics 2012-12-10 M. D. Maia

The influence of recent detections of a finite vacuum energy ("cosmological constant") on our formulation of anthropic conjectures, particularly the so-called Final Anthropic Principle is investigated. It is shown that non-zero vacuum…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Milan M. Cirkovic , Nick Bostrom

We consider Einstein gravity with positive cosmological constant coupled to matter in an asymptotically de Sitter universe with sphere boundary at timelike infinity. In this setting we show that, to one-loop order and at late time, the norm…

High Energy Physics - Theory · Physics 2025-08-01 Jordan Cotler , Kristan Jensen

The question of what is the total entropy of the universe, how it compares to the maximal entropy of de Sitter space, and how it is distributed across the universe's components, bears considerable importance for a number of reasons. Here,…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-23 Stefano Profumo , Liam Colombo-Murphy , Gabriela Huckabee , Maya Diaz Svensson , Stuti Garg , Ishan Kollipara , Alison Weber

Based on Eddington affine variational principle on a locally product manifold, we derive the separate Einstein space described by its Ricci tensor. The derived field equations split into two field equations of motion that describe two…

General Relativity and Quantum Cosmology · Physics 2016-05-31 Hemza Azri

We show that the class of four-dimensional Taub-Bolt(NUT) spacetimes with positive cosmological constant for some values of NUT charges are stable and have entropies that are greater than that of de Sitter spacetime, in violation of the…

High Energy Physics - Theory · Physics 2007-05-23 R. Clarkson , A. M. Ghezelbash , R. B. Mann

Entropy bounds render quantum corrections to the cosmological constant $\Lambda$ finite. Under certain assumptions, the natural value of $\Lambda$ is of order the observed dark energy density $\sim 10^{-10} {\rm eV}^4$, thereby resolving…

High Energy Physics - Theory · Physics 2008-11-26 Stephen D. H. Hsu

The paper aims to provide an explanation for the tiny value of the cosmological constant and the low vacuum energy density to represent the dark energy. To accomplish this, we will search for a fundamental principle of symmetry in…

General Relativity and Quantum Cosmology · Physics 2016-11-14 Cláudio Nassif

We investigate cosmic censorship in anti-de Sitter space in holographic models in which the ground state is described by a good singularity. These include supersymmetric truncations of string/M-theory, for which a positive-energy theorem…

High Energy Physics - Theory · Physics 2025-01-10 Marc Aragonès Fontboté , David Mateos , Guillem Pérez Martín , Wilke van der Schee , Javier G. Subils

If we assume that the initial conditions for the universe were such that there was no volume-extensive entropy `at the beginning of time' (which is true in Linde's chaotic inflation), we can formulate a covariant holographic bound on the…

High Energy Physics - Theory · Physics 2007-05-23 Michal Fabinger

We study a uniform and isotropic cosmology with a decaying vacuum energy density, in the realm of a model with a time varying gravitational "constant". We show that, for late times, such a cosmology is in accordance with the observed values…

General Relativity and Quantum Cosmology · Physics 2016-11-09 Saulo Carneiro

According to the universal entropy bound, the entropy (and hence information capacity) of a complete weakly self-gravitating physical system can be bounded exclusively in terms of its circumscribing radius and total gravitating energy. The…

Quantum Physics · Physics 2009-11-10 Jacob D. Bekenstein

The Cosmological Principle states that the universe is both homogeneous and isotropic. This, alone, is not enough to specify the global geometry of the spacetime. If we were able to measure both the Hubble constant and the energy density we…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Edward Malec , Niall Ó Murchadha

The present discussion contribution is some remarks concerning and review of the proposal by one of us (C. Balazs) to explain the cosmological constant by a/the principle of entropy. Used without further comment this principle of entropy…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-26 H. B. Nielsen , C. Balazs

We regard the background of space-time as a physical system composed of discrete volume elements at the Planck scale and get the internal energy of space-time by Debye model. A temperature-dependent minimum energy limit of the particles is…

General Relativity and Quantum Cosmology · Physics 2020-07-03 Qi-Qi Fan , Cong Li , Hao-Ran Zhang , Peng-Zhang He , Jian-Bo Deng

When the difference between changes in energy and entropy at a given temperature is correlated with the ratio between the same changes in energy and entropy at zero average free energy of an ensemble of similar but distinct molecule-sized…

General Physics · Physics 2009-06-17 Petr Zimak , Silvia Terenzi , Peter Strazewski

The cosmological constant, i.e., the energy density stored in the true vacuum state of all existing fields in the Universe, is the simplest and the most natural possibility to describe the current cosmic acceleration. However, despite its…

Astrophysics · Physics 2008-11-26 S. Carneiro , M. A. Dantas , C. Pigozzo , J. S. Alcaniz