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Homogeneous cosmological solutions are obtained in five dimensional space time assuming equations of state $ p = k\rho $ and $ p_{5}= \gamma\rho$ where p is the isotropic 3 - pressure and $p_{5}$, that for the fifth dimension. Using…

General Relativity and Quantum Cosmology · Physics 2009-11-11 D. Panigrahi , Y. Z. Zhang , S. Chatterjee

Quantum cosmological models are commonly described by means of semiclassical approximations in which a smooth evolution of the expectation values of elementary geometry operators replaces the classical and singular dynamics. The advantage…

General Relativity and Quantum Cosmology · Physics 2021-04-28 Przemysław Małkiewicz , Artur Miroszewski

In this paper we investigate dynamics of the modified loop quantum cosmology models using dynamical systems methods. Modifications considered come from the choice of the different field strength operator $\hat{F}$ and result in different…

General Relativity and Quantum Cosmology · Physics 2014-11-18 Orest Hrycyna , Jakub Mielczarek , Marek Szydlowski

p-Mechanics is a consistent physical theory which describes both quantum and classical mechanics simultaneously. We continue the development of p-mechanics by introducing the concept of states. The set of coherent states we introduce allow…

Quantum Physics · Physics 2007-05-23 Alastair Brodlie

Although cosmic expansion at very small distances is usually dismissed as entirely inconsequential, it appears that these extraordinarily small effects may in fact have a real and significant influence on our world. Calculations suggest…

General Physics · Physics 2015-06-26 C. L. Herzenberg

Several physical architectures allow for measurement-based quantum computing using sequential preparation of cluster states by means of probabilistic quantum gates. In such an approach, the order in which partial resources are combined to…

Quantum Physics · Physics 2009-11-13 K. Kieling , D. Gross , J. Eisert

We consider scalar perturbations of energy-density for a class of cosmological models where an early phase of accelerated expansion evolves, without any fine-tuning for graceful exit, towards the standard Friedman eras of observed universe.…

General Relativity and Quantum Cosmology · Physics 2011-05-10 S. Capozziello , G. Lambiase , G. Scarpetta

We consider the hypothesis that quantum mechanics is an approximation to another, cosmological theory, accurate only for the description of subsystems of the universe. Quantum theory is then to be derived from the cosmological theory by…

Quantum Physics · Physics 2007-05-23 Lee Smolin

We introduce a general statistical learning theory for processes that take as input a classical random variable and output a quantum state. Our setting is motivated by the practical situation in which one desires to learn a quantum process…

Quantum Physics · Physics 2025-02-27 Marco Fanizza , Yihui Quek , Matteo Rosati

Quantum algorithms have demonstrated provable speedups over classical counterparts, yet establishing a comprehensive theoretical framework to understand the quantum advantage remains a core challenge. In this work, we decode the quantum…

Quantum Physics · Physics 2025-11-11 Si-Qi Zhou , Jin-Min Liang , Ziheng Ding , Zhihua Chen , Shao-Ming Fei , Zhihao Ma

In the contemporary Cosmology, dark energy is modeled as a perfect fluid, having a very simple equation of state: pressure is proportional to dark energy density. As an alternative, I propose a more complex equation of state, with pressure…

General Physics · Physics 2009-11-04 Dragan Slavkov Hajdukovic

The Bohmian formulation of quantum mechanics is used in order to describe the measurement process in an intuitive way without a reduction postulate in the framework of a deterministic single system theory. Thereby the motion of the hidden…

Quantum Physics · Physics 2007-05-23 H. Geiger , G. Obermair , Ch. Helm

Fast moving classical variables can generate quantum mechanical behavior. We demonstrate how this can happen in a model. The key point is that in classically (ontologically) evolving systems one can still define a conserved quantum energy.…

Quantum Physics · Physics 2021-09-02 Gerard t Hooft

The expansion of our universe, when followed backward in time, implies that it emerged from a phase of huge density, the big bang. These stages are so extreme that classical general relativity combined with matter theories is not able to…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Martin Bojowald

Effective quantum cosmology is formulated with a realistic global internal time given by the electric vector potential. New possibilities for the quantum behavior of space-time are found, and the high-density regime is shown to be very…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Stephon Alexander , Martin Bojowald , Antonino Marciano , David Simpson

The acceleration of ultra high energy cosmic rays is conjectured to occur through various interactions with the electromagnetic fields in different astrophysical objects, like magnetic matter clumps, besides the well-known shock and…

High Energy Astrophysical Phenomena · Physics 2014-03-18 A. Tawfik , A. Saleh , M. T. Ghoneim , A. A. Hady

Every quantum state can be represented as a probability distribution over the outcomes of an informationally complete measurement. But not all probability distributions correspond to quantum states. Quantum state space may thus be thought…

Quantum Physics · Physics 2011-02-14 D. M. Appleby , Asa Ericsson , Christopher A. Fuchs

Recent astronomical observations of distant supernovae light-curves suggest that the expansion of the universe has recently begun to accelerate. Acceleration is created by an anti-gravitational repulsive stress, like that produced by a…

Astrophysics · Physics 2009-10-31 John Barrow , Rachel Bean , Joao Magueijo

We construct high-precision models of the Universe that contain radiation, a cosmological constant, and periodically distributed inhomogeneous matter. The density contrasts in these models are allowed to be highly non-linear, and the…

General Relativity and Quantum Cosmology · Physics 2017-02-24 Viraj A. A. Sanghai , Timothy Clifton

We extend various recent results regarding the derivation of effective cosmological Friedmann equations from the dynamics of group field theory (GFT). Restricting ourselves to a single GFT field mode (or fixed values of Peter-Weyl…

General Relativity and Quantum Cosmology · Physics 2022-01-11 Steffen Gielen , Axel Polaczek