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Using an approximate likelihood method adapted to band--power estimates, we analyze the ensemble of first generation cosmic microwave background anisotropy experiments to deduce constraints over a six--dimensional parameter space describing…

Astrophysics · Physics 2011-05-23 M. Le Dour , M. Douspis , J. G. Bartlett , A. Blanchard

We explicitly calculate the value of the cosmological constant, based on the recently developed theory connecting entropic gravity with quantum-events, induced by transactions, called transactional gravity. We suggest a novel interpretation…

General Relativity and Quantum Cosmology · Physics 2024-07-31 Andreas Schlatter

Taking into account a fractal structure for the black hole horizon, Barrow argued that the area law of entropy is modified due to quantum-gravitational effects (Barrow in Phys Lett B 808:135643,…

General Relativity and Quantum Cosmology · Physics 2022-05-20 Mahnaz Asghari , Ahmad Sheykhi

Observations conducted over the last few decades show that the expansion of the Universe is accelerating. In the standard model of cosmology, this accelerated expansion is attributed to a dark energy in the form of a cosmological constant.…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-22 Joseph Ryan

Anthropic principle can help us to understand many properties of our world. However, for a long time this principle seemed too metaphysical and many scientists were ashamed to use it in their research. I describe here a justification of the…

High Energy Physics - Theory · Physics 2007-05-23 Andrei Linde

We reexamine constraints on the spatial size of closed toroidal models with cold dark matter and the cosmological constant from cosmic microwave background. We carry out Bayesian analyses using the Cosmic Background Explorer (COBE) data…

Astrophysics · Physics 2009-11-07 Kaiki Taro Inoue , Naoshi Sugiyama

Prediction in quantum cosmology requires a specification of the universe's quantum dynamics and its quantum state. We expect only a few general features of the universe to be predicted with probabilities near unity conditioned on the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 James B. Hartle

We consider structure formation and CMB anisotropies in a closed universe, both with and without a cosmological constant. The CMB angular power spectrum and the matter transfer function are presented, along with a discussion of their…

Astrophysics · Physics 2009-08-18 Martin White , Douglas Scott

The curvature parameter tension between Planck 2018, cosmic microwave background lensing, and baryon acoustic oscillation data is measured using the suspiciousness statistic to be 2.5 to 3$\sigma$. Conclusions regarding the spatial…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-10 Will Handley

In any quantum theory of gravity we do expect corrections to Einstein gravity to occur. Yet, at fundamental level, it is not apparent what the most relevant corrections are. We argue that the generic curvature square corrections present in…

High Energy Physics - Theory · Physics 2011-02-09 Ishwaree P. Neupane , Naresh Dadhich

In this paper we suppose that the cosmological constant will change when the universe expends. For a general consideration, the cosmological constant is assumed to be a function of scale factor and Hubble constant. According to the ADM…

Cosmology and Nongalactic Astrophysics · Physics 2010-08-03 Jin-Zhang Tang , Qiang Xu

Quantum physics, despite its observables being intrinsically of a probabilistic nature, does not have a quantum entropy assigned to them. We propose a quantum entropy that quantify the randomness of a pure quantum state via a conjugate pair…

Quantum Physics · Physics 2022-10-05 Davi Geiger , Zvi M. Kedem

I use Bousso's causal diamond measure to make a statistical prediction for the dark matter abundance, assuming an axion with a large decay constant f_a >> 10^{12} GeV. Using a crude approximation for observer formation, the prediction…

High Energy Physics - Theory · Physics 2015-05-13 Ben Freivogel

The existence of multiple regions of space beyond the observable Universe (within the so-called "multiverse") where the vacuum energy density takes different values, has been postulated as an explanation for the low non-zero value observed…

Astrophysics · Physics 2009-11-11 Abraham Loeb

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 propose a class of theories that can limit scalars constructed from the extrinsic curvature. Applied to cosmology, this framework allows us to control not only the Hubble parameter but also anisotropies without the problem of…

General Relativity and Quantum Cosmology · Physics 2020-10-06 Yuki Sakakihara , Daisuke Yoshida , Kazufumi Takahashi , Jerome Quintin

Bayesian model averaging is a procedure to obtain parameter constraints that account for the uncertainty about the correct cosmological model. We use recent cosmological observations and Bayesian model averaging to derive tight limits on…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-07 M. Vardanyan , R. Trotta , J. Silk

A hypothesis of curvature pressure is used to derive a static and stable cosmology with a tired-light redshift. The idea is that the high energy particles in the inter-galactic medium do not travel along geodesics because of the strong…

Astrophysics · Physics 2015-06-24 David F. Crawford

The entropy of the observable universe is increasing. Thus, at earlier times the entropy was lower. However, the cosmic microwave background radiation reveals an apparently high entropy universe close to thermal and chemical equilibrium. A…

General Relativity and Quantum Cosmology · Physics 2017-10-11 Vihan M. Patel , and Charles H. Lineweaver

Time is a parameter playing a central role in our most fundamental modelling of natural laws. Relativity theory shows that the comparison of times measured by different clocks depends on their relative motion and on the strength of the…

General Relativity and Quantum Cosmology · Physics 2017-07-25 Hauret Clementine , Magain Pierre , Biernaux Judith