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Related papers: Towards a non-anthropic solution to the cosmologic…

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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

In this paper we consider the implications of a cosmological constant for the evolution of the universe, under a set of assumptions motivated by the holographic and horizon complementarity principles. We discuss the ``causal patch"…

High Energy Physics - Theory · Physics 2009-11-07 Lisa Dyson , Matthew Kleban , Leonard Susskind

This paper provides a prospectus for a new way of thinking about the wavefunction of the universe: a $\Psi$-epistemic quantum cosmology. We present a proposal that, if successfully implemented, would resolve the cosmological measurement…

General Relativity and Quantum Cosmology · Physics 2017-11-15 Peter W. Evans , Sean Gryb , Karim P. Y. Thébault

After commenting briefly on the role of the typicality assumption in science, we advocate a phenomenological approach to the cosmological measure problem. Like any other theory, a measure should be simple, general, well-defined, and…

High Energy Physics - Theory · Physics 2008-11-26 Raphael Bousso , Ben Freivogel , I-Sheng Yang

Treating the metric as a classical background field, we show that the cosmological constant does not run with the renormalization scale -- contrary to some claims in the literature.

High Energy Physics - Theory · Physics 2008-11-26 Robert Foot , Archil Kobakhidze , Kristian L. McDonald , Raymond R. Volkas

For bouncing cosmologies such as the ekpyrotic/cyclic scenarios we show that it is possible to make predictions for density perturbations which are independent of the details of the bouncing phase. This can be achieved, as in inflationary…

High Energy Physics - Theory · Physics 2009-11-10 Paolo Creminelli , Alberto Nicolis , Matias Zaldarriaga

We investigate the line element of spacetime around a linear cosmic string in the presence of a cosmological constant. We obtain the metric and argue that it should be discarded because of asymptotic considerations. Then a time dependent…

General Relativity and Quantum Cosmology · Physics 2009-01-05 Amir H. Abbassi , Amir M. Abbassi

There are some theoretical arguments about possible variations of fundamental constants with cosmic time. We review the fact that all conversion factors depend on these quantities and consider how their variations may affect transformations…

General Relativity and Quantum Cosmology · Physics 2020-12-29 Yousef Bisabr

The idea of possible time or space variations of the `fundamental' constants of nature, although not new, is only now beginning to be actively considered by large numbers of researchers in the particle physics, cosmology and astrophysics…

Astrophysics · Physics 2009-11-07 C. J. A. P. Martins

A new way is proposed to cancel the cosmological constant. The proposal involves the metric determinant acting as a type of self-adjusting $q$-field without need of a fine-tuned chemical potential. Since the determinant of the metric now…

High Energy Physics - Theory · Physics 2022-12-12 F. R. Klinkhamer

The Cosmic Defect theory has been confronted with four observational constraints: primordial nuclear species abundances emerging from the big bang nucleosynthesis; large scale structure formation in the universe; cosmic microwave background…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 N. Radicella , M. Sereno , A. Tartaglia

Evidence for fine-tuning of physical parameters suitable for life can perhaps be explained by almost any combination of providence, coincidence or multiverse. A multiverse usually includes parts unobservable to us, but if the theory for it…

High Energy Physics - Theory · Physics 2007-05-23 Don N. Page

Probably not, because there are lots of manifestly unanthropic ways of producing entropy. We demonstrate that the Causal Entropic Principle (CEP), as a replacement for the anthropic principle to explain the properties of the observed…

High Energy Physics - Theory · Physics 2008-12-05 Irit Maor , Thomas W. Kephart , Lawrence M. Krauss , Y. Jack Ng , Glenn D. Starkman

Hubble tension and the search for preferred direction are two crucial unresolved issues in modern cosmology. Different measurements of the Hubble constant provide significantly different values, and this is known as the Hubble tension. The…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-01 Rahul Kumar Thakur , Meghendra Singh , Shashikant Gupta , Rahul Nigam

Despite the many outstanding cosmological observations leading to a strong evidence for a nonvanishing cosmological constant (CC) term in the gravitational field equations, the theoretical status of this quantity seems to be lagging well…

High Energy Physics - Theory · Physics 2010-02-11 Ilya L. Shapiro , Joan Sola

Based on the assertion that the cosmological constant problem is essentially a quantum gravity problem, the framework which addresses the cosmological constant problem should also bear a picture for the ``quantum space-time''. In this talk…

High Energy Physics - Phenomenology · Physics 2009-10-07 M. M. Sheikh-Jabbari

In this paper we modify the EiBI model to realize a varying cosmological constant which is determined by matter distribution. We find that the Newton's constant is also variable and its change is related to the change of cosmological…

General Relativity and Quantum Cosmology · Physics 2019-11-13 Haomin Rao , Dehao Zhao

The discovery that the expansion of the universe is accelerating in time is a major discovery which still awaits adequate explanation. It is generally agreed that this implies a cosmic repulsion as a result of the existence of a…

General Physics · Physics 2008-11-26 R. F. O'Connell

The lower limit on the age of the universe derived from globular cluster dating techniques, which previously strongly motivated a non-zero cosmological constant, has now been dramatically reduced, allowing consistency for a flat matter…

Astrophysics · Physics 2011-02-11 Lawrence M. Krauss

We discuss several issues related to a recent proposal for defining classical spatial averages to be used in the so-called cosmological backreaction problem. In the large averaging-volume limit all gauge dependence disappears and different…

General Relativity and Quantum Cosmology · Physics 2011-07-14 Giovanni Marozzi