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We study closed universes in holographic theories of quantum gravity. We argue that within any fixed theory, factorization implies there is one unique closed universe state. The wave function of any state that can be prepared by the path…

High Energy Physics - Theory · Physics 2025-02-17 Mykhaylo Usatyuk , Ying Zhao

We solve Einstein's equation with Robertson-Walker metric as an initial-value problem, using as the source of gravity a Halpern-Huang real scalar field, which was derived from renormalization-group analysis, with a potential that exhibits…

General Relativity and Quantum Cosmology · Physics 2010-11-18 Kerson Huang , Hwee-Boon Low , Roh-Suan Tung

A new version of holographic principle for cosmology is proposed, which dictates that particle entropy within `cosmological apparent horizon' should not exceed gravitational entropy associated with the apparent horizon. It is shown that, in…

High Energy Physics - Theory · Physics 2010-04-06 Dongsu Bak , Soo-Jong Rey

We consider a simplified model of quantum gravity using a mini-superspace description of an isotropic and homogeneous universe with dust. We derive the corresponding Friedmann equations for the scale factor, which now contain a dependence…

General Relativity and Quantum Cosmology · Physics 2020-04-03 Thibaut Demaerel , Christian Maes , Ward Struyve

From an observational perspective cosmology is today in excellent shape - advances in instrumentation and data processing have enabled us to study the universe in detail back to when the first galaxies formed, map the fluctuations in the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Subir Sarkar

It has been shown that Friedmann equation of FRW universe can be derived from the idea which says cosmic space is emergent as cosmic time progresses and our universe is expanding towards the state with the holographic equipartition by…

High Energy Physics - Theory · Physics 2015-06-15 Fei-Quan Tu , Yi-Xin Chen

As is well known, black hole entropy is proportional to the area of the horizon suggesting a holographic principle wherein all degrees of freedom contributing to the entropy reside on the surface. In this note, we point out that large scale…

General Physics · Physics 2013-12-19 C. Sivaram , Kenath Arun

The most radical version of the holographic principle asserts that all information about physical processes in the world can be stored on its surface. This formulation is at odds with inflationary cosmology, which implies that physical…

High Energy Physics - Theory · Physics 2009-09-29 Nemanja Kaloper , Andrei Linde

There is a formal analogy between the evolution of the universe, when this is seen as a trajectory in the minisuperspace, and the worldline followed by a test particle in a curved spacetime. The analogy can be extended to the quantum realm,…

General Relativity and Quantum Cosmology · Physics 2018-12-31 Salvador J. Robles-Pérez

We argue that standard tools of holography can be used to describe fully non-perturbative microscopic models of cosmology in which a period of accelerated expansion may result from the positive potential energy of time-dependent scalar…

High Energy Physics - Theory · Physics 2022-03-23 Stefano Antonini , Petar Simidzija , Brian Swingle , Mark Van Raamsdonk

We examine a simple theoretical model to estimate (by fine tuning condition) the value of the cosmological constant. We assume, in analogy with holographic principle, that cosmological constant, like classical surface tension coefficient in…

Astrophysics · Physics 2008-01-21 V. Pankovic , S. Ciganovic , J. Ivanovic , R. Glavatovic , P. Grujic

Universe structure emerges in the unreduced, complex-dynamic interaction process with the simplest initial configuration (two attracting homogeneous fields, quant-ph/9902015). The unreduced interaction analysis gives intrinsically creative…

General Physics · Physics 2007-05-23 Andrei P. Kirilyuk

Cosmology is undergoing an explosive period of activity, fueled both by new, accurate astrophysical data and by innovative theoretical developments. Cosmological parameters such as the total density of the Universe and the rate of…

Astrophysics · Physics 2007-05-23 A. S. Sakharov , H. Hofer

The spatial expansion of the universe can be described as the emergence of space with the progress of cosmic time, through a simple equation, $\Delta V = \Delta t\left(N_{surf}- N_{bulk}\right)$. This law of emergence suggested by…

General Relativity and Quantum Cosmology · Physics 2021-05-04 Krishna P B , Titus K Mathew

A holistic view of the cosmological appearance and development of space is obtained by studying space as a spherically closed surface of a 4-sphere in a zero energy balance between motion and gravitation. Such an approach re-establishes…

Astrophysics · Physics 2009-11-13 Tuomo Suntola

We study the classical and quantum models of a flat Friedmann-Robertson-Walker (FRW) space-time, coupled to a perfect fluid, in the context of the consensus and a gauge-fixed Lagrangian frameworks. It is shown that, either in the usual or…

General Relativity and Quantum Cosmology · Physics 2015-03-19 Babak Vakili

The Friedmann equation is derived for a Newtonian universe. Changing mass density to energy density gives exactly the Friedmann equation of general relativity. Accounting for work done by pressure then yields the two Einstein equations that…

Astrophysics · Physics 2015-06-24 Thomas F. Jordan

Using gauge formulation of gravity the three-dimensional SU(2) YM theory equations of motion are presented in equivalent form as FRW cosmological equations. With the radiation, the particular (periodic, big bang-big crunch)…

High Energy Physics - Theory · Physics 2009-09-17 Shin'ichi Nojiri , Sergei D. Odintsov

We investigated the cosmology in a higher-curvature gravity where the dimensionality of spacetime gives rise to only quantitative difference, contrary to Einstein gravity. We found exponential type solutions for flat isotropic and…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Y. Ezawa , H. Iwasaki , M. Ohmori , S. Ueda , N. Yamada , T. Yano

The cosmology of brane induced gravity in six infinite dimensions is investigated. It is shown that a brane with Friedmann-Robertson-Walker symmetries necessarily acts as a source of cylindrically symmetric gravitational waves, so called…

General Relativity and Quantum Cosmology · Physics 2015-01-08 Florian Niedermann , Robert Schneider , Stefan Hofmann , Justin Khoury