English
Related papers

Related papers: Note on the classical solutions of Friedmann's equ…

200 papers

In a variety of systems which exhibit aging, the two-time response function scales as $R(t,s)\approx s^{-1-a} f(t/s)$. We argue that dynamical scaling can be extended towards conformal invariance, obtaining thus the explicit form of the…

High Energy Physics - Theory · Physics 2012-10-18 Malte Henkel , Michel Pleimling , Claude Godreche , Jean-Marc Luck

In a universe where, according to the standard cosmological models, some 97% of the total mass-energy is still "missing in action" it behooves us to spend at least a little effort critically assessing and exploring radical alternatives.…

General Relativity and Quantum Cosmology · Physics 2017-11-28 Matt Visser

Temporal Relationalism (TR) is that there is no time for the universe as a whole at the primary level. Time emerges rather at a secondary level; one compelling idea for this is Mach's `time is to be abstracted from change'. TR leads to, and…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Edward Anderson

The acclaimed merits of analytical solutions based on a fictitious time developed in the 1970's were partially overvalued due to a common misuse of classical analytical solutions based on the physical time that were taken as reference. With…

Dynamical Systems · Mathematics 2022-05-06 Martin Lara

Observational cosmology provides us with a large number of high precision data which are used to derive models trying to reproduce ``on the mean'' our observable patch of the Universe. Most of these attempts are achieved in the framework of…

Astrophysics · Physics 2011-11-10 Marie-Noëlle Célérier

Inconsistencies are pointed out in a recent proposal [L. Diosi, Phys. Rev. A 80, 064104 (2009); arXiv:0905.3908v1] for a quantum version of the classical linear Boltzmann equation.

Quantum Physics · Physics 2010-09-28 Klaus Hornberger , Bassano Vacchini

This essay examines our fundamental conceptions of time, spacetime, the asymmetry of time, and the motion of a quantum mechanical particle. The concept of time has multiple meanings and these are often confused in the literature and must be…

General Relativity and Quantum Cosmology · Physics 2014-08-15 Gerald E. Marsh

If our Universe is allowed to absorb baby universes, one obtains a modified Friedmann equation that can explain the late time acceleration of our Universe and there is no need for a cosmological constant. In addition the modified Friedmann…

General Relativity and Quantum Cosmology · Physics 2024-01-17 Jan Ambjorn , Yoshiyuki Watabiki

It is shown that the Schrodinger equation is a byproduct of more deterministic Boltzmann-like equation. All physical information is derived from the solution of this equation, which is a function of space and momentum. The additional terms…

Quantum Physics · Physics 2007-05-23 A. M. Ghorbanzadeh

In this article we follow a previously developed theoretical approach, based in the tools of the singular semi-Riemannian geometry, to push the limits of time beyond the primordial spacetime singularity. By complexifying the…

General Relativity and Quantum Cosmology · Physics 2021-05-19 C. A. Z. Vasconcellos , P. O. Hess , D. Hadjimichef , B. Bodmann , M. Razeira , G. L. Volkmer

When compared to quantum mechanics, classical mechanics is often depicted in a specific metaphysical flavour: spatio-temporal realism or a Newtonian "background" is presented as an intrinsic fundamental classical presumption. However, the…

General Physics · Physics 2025-05-30 C. Baumgarten

Recently, Falomir, Gamboa, Mendez, Gondolo and Maldonado proposed a bicosmology scenario [1-4] for solving some cosmological problems related to inflation, dark matter, and thermal history of the universe. Their plan is to introduce…

General Relativity and Quantum Cosmology · Physics 2022-12-27 Nahomi Kan , Takuma Aoyama , Kiyoshi Shiraishi

We study the evolution of the universe in the presence of inflaton, matter, radiation, and holographic dark energy. The time evolution of the scale factor is obtained by solving the Friedmann equation of the universe with a good…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Hyeong-Chan Kim , Jae-Weon Lee , Jungjai Lee

Scientific discussions of the arrow of time often get quite confusing due to highly complex systems they deal with. Popular literature then often coveys messages that tend to get lost in translation. The purpose of this note is to demystify…

Popular Physics · Physics 2024-08-29 Zura Kakushadze

We present a series of results focused on the decay in time of solutions of classical and anomalous diffusive equations in a bounded domain. The size of the solution is measured in a Lebesgue space, and the setting comprises time-fractional…

Analysis of PDEs · Mathematics 2019-08-09 Elisa Affili , Serena Dipierro , Enrico Valdinoci

Perhaps the most significant drawback, which the Copenhagen interpretation (still the most popular interpretation of quantum theory) suffers from, is the classical-quantum divide between the large classical systems that carry out…

Quantum Physics · Physics 2014-07-24 Arkady Bolotin

In the previous paper we examined the third quantization of the $f(R)$-type gravity and studied the Heisenberg uncertainty relation of the universe in the example of $f(R)=R^2$. In this work the Heisenberg uncertainty relation of the…

General Relativity and Quantum Cosmology · Physics 2019-04-30 Yoshiaki Ohkuwa , Yasuo Ezawa

An equation describing a one-dimensional model for the freezing of lakes is shown to be formally analogous to the Friedmann equation of cosmology. The analogy is developed and used to speculate on the change between two hypothetical…

General Relativity and Quantum Cosmology · Physics 2020-02-26 Valerio Faraoni

The interpretation of the expanding universe as an expansion of space has recently been challenged. From the geodesic equation in Friedmann universe models and the empty Milne model, we argue that a Newtonian or special relativistic…

Astrophysics · Physics 2009-11-11 Oyvind Gron , Oystein Elgaroy

Recent observations indicate that the Universe is not transparent but partially opaque due to absorption of light by ambient cosmic dust. This implies that the Friedmann equations valid for the transparent universe must be modified for the…

General Physics · Physics 2022-06-06 Václav Vavryčuk