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Related papers: The Active Universe

200 papers

The universe is smooth on large scales but very inhomogeneous on small scales. Why is the spacetime on large scales modeled to a good approximation by the Friedmann equations? Are we sure that small-scale non-linearities do not induce a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Daniel Baumann , Alberto Nicolis , Leonardo Senatore , Matias Zaldarriaga

A generalized reciprocal theorem is formulated for the motion and hydrodynamic force moments of an active particle in an arbitrary background flow of a (weakly nonlinear) complex fluid. This formalism includes as special cases a number of…

Fluid Dynamics · Physics 2017-10-11 Gwynn J. Elfring

Complex systems throughout Nature display structures and functions that are built and maintained, at least in part, by optimal energies flowing through them--not specific, ideal values, rather ranges in energy rate density below which…

Popular Physics · Physics 2014-06-25 Eric J. Chaisson

Loop quantum cosmology (LQC) is very powerful to deal with the behavior of early universe. And the effective loop quantum cosmology gives a successful description of the universe in the semiclassical region. We consider the apparent horizon…

General Relativity and Quantum Cosmology · Physics 2010-04-15 Li-Fang Li , Jian-Yang Zhu

A new cosmological theory is proposed in the theoretical framework of modified gravity theories which is based on a tachyonic field non-minimally coupled with a specific topological invariant constructed with third order contractions of the…

General Relativity and Quantum Cosmology · Physics 2022-12-14 Mihai Marciu

We exploit the parallel between dynamical black holes and cosmological spacetimes to describe the evolution of Friedmann-Lema\^itre-Robertson-Walker universes from the point of view of an observer in terms of the dynamics of the apparent…

General Relativity and Quantum Cosmology · Physics 2015-10-07 Pierre Binétruy , Alexis Helou

Let a number, N, of particles interact classically through Newton's Laws of Motion and Newton's inverse square Law of Gravitation. The resulting equations of motion provide an approximate mathematical model with numerous applications in…

Astrophysics · Physics 2007-05-23 Douglas C. Heggie

The suggested approach makes it possible to produce a consistent description of motions of a physical system. It is shown that the concept of force fields defining the systems dynamics is equivalent to the choice of the corresponding metric…

General Physics · Physics 2015-06-11 S. V. Siparov

The Friedmann equations of universe dynamics describe the infinite number of the Friedmannian models of universe. The consistent and distinguished relativistic, classical-mechanical, quantum-mechanical and formal-logical analysis of the…

Astrophysics · Physics 2008-12-19 V. Skalsky

Much of the twentieth century physics has considered rigid laws-- even Quantum Mechanics and Statistical Mechanics were based on such laws. These laws operated in a smooth spacetime manifold. However more recent approaches as in Quantum…

General Physics · Physics 2007-05-23 Burra G. Sidharth

Beings, animate or inanimate, are dynamical systems which continuously interact with the (external and /or internal) environment through the physical or physiologic interfaces of their Kantian (representational) realities. And the nature of…

Neurons and Cognition · Quantitative Biology 2019-09-03 Jahan N. Schad

In the context of thermodynamics applied to our cosmological apparent horizon, we explicit in greater details our previous work which established the Friedmann Equations from projection of Hayward's Unified First Law. In particular, we show…

General Relativity and Quantum Cosmology · Physics 2015-02-17 Alexis Helou

We survey some of the connections linking complex dynamics to other fields of mathematics and science. We hope to show that complex dynamics is not just interesting on its own but also has value as an applicable theory.

Dynamical Systems · Mathematics 2020-07-01 Alexandre DeZotti

Self-propulsion allows living systems to display unusual collective behavior. Unlike passive systems in thermal equilibrium, active matter systems are not constrained by conventional thermodynamic laws. A question arises however as to what…

Soft Condensed Matter · Physics 2015-03-18 Sho C. Takatori , John F. Brady

We investigate the behaviour of exact closed bouncing Friedmann universes in theories with varying constants. We show that the simplest BSBM varying-alpha theory leads to a bouncing universe. The value of alpha increases monotonically,…

Astrophysics · Physics 2009-11-10 John D. Barrow , Dagny Kimberly , Joao Magueijo

We consider the evolution of a flat Friedmann-Roberstson-Walker Universe in a higher derivative theories, including $\alpha R^{2}$ terms to the Einstein-Hilbert action in the presence of a variable gravitational and cosmological constants.…

General Relativity and Quantum Cosmology · Physics 2014-11-17 P. S. Debnath , B. C. Paul

An explicit and complete set of constants of the motion are constructed algorithmically for Friedmann-Lema\^{i}tre-Robertson-Walker (FLRW) models consisting of an arbitrary number of non-interacting species. The inheritance of constants of…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Kayll Lake

We construct an effective action for gravity in which all homogeneous solutions are nonsingular. In particular, there is neither a big bang nor a big crunch. The action is a higher derivative modification of Einstein's theory constructed in…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Robert H. Brandenberger

Asymptotically safe theories of gravitation have received great attention in recent times. In this framework an effective action embodying the basic features of the renormalized flow around the non-gaussian fixed point is derived and its…

High Energy Physics - Theory · Physics 2015-06-04 Alfio Bonanno

The dynamics of the expanding universe is analyzed in terms of the quantum geometrodynamical model. It is shown that the equations of quantum theory in the form of the eigenvalues equation similar to the stationary Schr\"{o}dinger equation…

General Relativity and Quantum Cosmology · Physics 2013-11-22 V. E. Kuzmichev , V. V. Kuzmichev