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Notoriously, the two main problems of the standard $\Lambda$CDM model of cosmology are the cosmological constant $\Lambda$ and the cold dark matter, CDM. This essay shows that both the $\Lambda$ and the CDM arise as integration constants in…

General Relativity and Quantum Cosmology · Physics 2021-03-11 Priidik Gallagher , Tomi Koivisto

We describe a mechanism that drives the Cosmological Constant to zero value. This mechanism is based on the quantum triviality of $\lambda \phi^4$ field theory and works in $AdS$ space. Some subtleties of the model are discussed.

High Energy Physics - Theory · Physics 2010-04-05 R. Jackiw , Carlos Nunez , S. -Y. Pi

For a universe presently dominated by static or dynamic vacuum energy, cosmological constant (LCDM) or quintessence (QCDM), we calculate the asymptotic collapsed mass fraction as function of the present ratio of vacuum energy to clustered…

Astrophysics · Physics 2016-11-03 Sidney Bludman

We demonstrate that, in the context of the $\Lambda$CDM model, it is in principle possible to measure the value of the cosmological constant by tracing, across cosmic time, the evolution of the turnaround radius of cosmic structures. The…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-18 Dimitrios Tanoglidis , Vasiliki Pavlidou , Theodore Tomaras

A precise measurement of the curvature of the Universe is of primeval importance for cosmology since it could not only confirm the paradigm of primordial inflation but also help in discriminating between different early Universe scenarios.…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-27 Eleonora Di Valentino , Luis A. Anchordoqui , Ozgur Akarsu , Yacine Ali-Haimoud , Luca Amendola , Nikki Arendse , Marika Asgari , Mario Ballardini , Spyros Basilakos , Elia Battistelli , Micol Benetti , Simon Birrer , François R. Bouchet , Marco Bruni , Erminia Calabrese , David Camarena , Salvatore Capozziello , Angela Chen , Jens Chluba , Anton Chudaykin , Eoin Ó Colgáin , Francis-Yan Cyr-Racine , Paolo de Bernardis , Javier de Cruz Pérez , Jacques Delabrouille , Celia Escamilla-Rivera , Agnès Ferté , Fabio Finelli , Wendy Freedman , Noemi Frusciante , Elena Giusarma , Adrià Gómez-Valent , Will Handley , Ian Harrison , Luke Hart , Alan Heavens , Hendrik Hildebrandt , Daniel Holz , Dragan Huterer , Mikhail M. Ivanov , Shahab Joudaki , Marc Kamionkowski , Tanvi Karwal , Lloyd Knox , Suresh Kumar , Luca Lamagna , Julien Lesgourgues , Matteo Lucca , Valerio Marra , Silvia Masi , Sabino Matarrese , Arindam Mazumdar , Alessandro Melchiorri , Olga Mena , Laura Mersini-Houghton , Vivian Miranda , Cristian Moreno-Pulido , David F. Mota , Jessica Muir , Ankan Mukherjee , Florian Niedermann , Alessio Notari , Rafael C. Nunes , Francesco Pace , Andronikos Paliathanasis , Antonella Palmese , Supriya Pan , Daniela Paoletti , Valeria Pettorino , Francesco Piacentini , Vivian Poulin , Marco Raveri , Adam G. Riess , Vincenzo Salzano , Emmanuel N. Saridakis , Anjan A. Sen , Arman Shafieloo , Anowar J. Shajib , Joseph Silk , Alessandra Silvestri , Martin S. Sloth , Tristan L. Smith , Joan Solà , Carsten van de Bruck , Licia Verde , Luca Visinelli , Benjamin D. Wandelt , Deng Wang , Jian-Min Wang , Anil K. Yadav , Weiqiang Yang

We have studied the closed universe model with the variable cosmological term, which is presented as a sum of two terms: Lambda=Lambda_0 -k R. First term Lambda_0 is a constant and it is describing a sum of quantum field's zero…

General Relativity and Quantum Cosmology · Physics 2007-05-23 P. I. Fomin , P. A. Nakaznoy , S. I. Vilchinskyi

Models of the very early universe, including inflationary models, are argued to produce varying universe domains with different values of fundamental constants and cosmic parameters. Using the cosmological hydrodynamical simulation code…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-10 Luke A. Barnes , Pascal J. Elahi , Jaime Salcido , Richard G. Bower , Geraint F. Lewis , Tom Theuns , Matthieu Schaller , Robert A. Crain , Joop Schaye

The idea here is to set the cosmical constant $\lambda$ proportional to the scalar of the stress-energy tensor of the ordinary matter. We investigate the evolution of the scale factor in a cosmological model in which the cosmological…

Astrophysics · Physics 2007-05-23 V. Majernik

With attempts to quench the cosmological constant $\Lambda$ having so far failed, we instead investigate what could be done if $\Lambda$ is not quenched and actually gets to be as big as elementary particle physics suggests. Since the…

Astrophysics · Physics 2007-05-23 Philip D. Mannheim

The asymptotic structure of the gravitational field of isolated systems has been analyzed in great detail in the case when the cosmological constant $\Lambda$ is zero. The resulting framework lies at the foundation of research in diverse…

General Relativity and Quantum Cosmology · Physics 2015-10-21 Abhay Ashtekar , Beatrice Bonga , Aruna Kesavan

In quantum cosmology the closed universe can spontaneously nucleate out of the state with no classical space and time. For the universe filled with a vacuum of constant energy density the semiclassical tunneling nucleation probability can…

High Energy Physics - Theory · Physics 2016-09-06 A. V. Yurov , V. A. Yurov

The common nature of dark matter and dark energy is argued in [1] based on the approach that the cosmological constant \Lambda enters the weak-field General Relativity following from Newton theorem on the "sphere-point mass" equivalency…

General Physics · Physics 2019-02-27 V. G. Gurzadyan , A. Stepanian

The primary purpose of this work is the provision of accurate, analytic, evolutionary templates for cosmological parameters and fundamental constants in a dynamical cosmology. A flat quintessence cosmology with a dark energy potential that…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-17 Rodger I. Thompson

We conjecture a time dependent Lambda(t), in terms of the Gaussian curvature of the causal horizon, which is nonvanishing even in Minkowski space due to the lack of informations beyond the light cone. Using the Heisenberg Principle, the…

High Energy Physics - Theory · Physics 2007-05-23 Hristu Culetu

The observed value $\Lambda_{\rm obs}$ of the cosmological constant $\Lambda$ is extremely smaller than theoretical expectations, and the anthropic argument has been proposed as a solution to this problem because galaxies do not form when…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-09 Tomonori Totani , Hidetoshi Omiya , Takahiro Sudoh , Masakazu A. R. Kobayashi , Masahiro Nagashima

Independent tests aiming to constrain the value of the cosmological constant $\Lambda$ are usually difficult because of its extreme smallness $\left(\Lambda \simeq 1\times 10^{-52}~\textrm{m}^{-2},~\textrm{or}~2.89\times…

General Relativity and Quantum Cosmology · Physics 2018-03-28 Lorenzo Iorio

The tensions between the values of Hubble constant obtained from the early and the late Universe data pose a significant challenge to modern cosmology. Possible modifications of the flat homogeneous isotropic cosmological {\Lambda}CDM model…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-14 S. L. Parnovsky

We present limits on the cosmological constant from the statistics of gravitational lenses using newly completed quasar surveys, new lens data, and a range of lens models. The formal limit is $\lambda_0 < 0.66$ at 95\% confidence in flat…

Astrophysics · Physics 2009-10-28 C. S. Kochanek

We study dynamics of $\Lambda(t)$ cosmological models which are a natural generalization of the standard cosmological model (the $\Lambda$CDM model). We consider a class of models: the ones with a prescribed form of…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-29 Marek Szydlowski , Aleksander Stachowski

For decades, H_0 and q_0 were the quest of cosmology, as they promised to characterize our "world model" without reference to a specific cosmological framework. Using Monte Carlo simulations, we show that q_0 cannot be directly measured…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Abraham R. Neben , Michael S. Turner