# Adventures in Friedmann cosmology: A detailed expansion of the cosmological Friedmann equations

@article{Nemiroff2007AdventuresIF, title={Adventures in Friedmann cosmology: A detailed expansion of the cosmological Friedmann equations}, author={Robert J. Nemiroff and Bijunath R. Patla}, journal={American Journal of Physics}, year={2007}, volume={76}, pages={265-276} }

The general relativistic cosmological Friedmann equations, which describe how the scale factor of the universe evolves, are expanded explicitly to include energy forms not usually seen. The evolution of the universe as predicted by the Friedmann equations when dominated by a single, isotropic, stable, static, perfect-fluid energy form is discussed for different values of the gravitational pressure to density ratio w. These energy forms include phantom energy (w 1∕3). A brief history and…

## 29 Citations

### Qualitative study of perfect-fluid Friedmann-Lemaître-Robertson-Walker models with a cosmological constant

- Physics
- 2012

The evolution of spatially homogeneous and isotropic cosmological models containing a perfect fluid with equation of state p = wρ and a cosmological constant Λ is investigated for arbitrary…

### FIRST-ORDER QUANTUM-GRAVITATIONAL CORRECTION TO FRIEDMANNIAN COSMOLOGY FROM COVARIANT, HOLOMORPHIC SPINFOAM COSMOLOGY

- Physics
- 2013

The first-order loop quantum gravity correction of the simplest, classical general relativistic Friedmann Hamiltonian constraint, emerging from a holomorphic spinfoam cosmological model peaked on…

### Stability of Friedmann equation with respect to small changes in the density parameter

- Mathematics, Physics
- 2015

We show that the solution of the Friedmann equation for a universe with matter and cosmological constant is stable with respect to small changes in the density parameter Ω0. We find an expression for…

### First-order quantum-gravitational correction to Friedmannian cosmology from covariant, holomorphic spinfoam cosmology

- Physics
- 2010

The first-order loop quantum gravity correction of the simplest, classical general relativistic Friedmann Hamiltonian constraint, emerging from a holomorphic spinfoam cosmological model peaked on…

### Explicit integration of Friedmann's equation with nonlinear equations of state

- Physics, Mathematics
- 2015

In this paper we study the integrability of the Friedmann equations, when the equation of state for the perfect-fluid universe is nonlinear, in the light of the Chebyshev theorem. A series of…

### QUASI-PERIODIC SOLUTIONS OF EINSTEIN-FRIEDMAN EQUATIONS

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- 2010

A new quasi-periodic solutions of Einstein-Friedman equations are presented here. The equation for law of energy saving is proved to be transformed to the proper Abel ordinary differential equation.…

### QUASI-PERIODIC SOLUTIONS OF

- Physics, Mathematics
- 2014

A new quasi-periodic solutions of Einstein-Friedman equations are presented here. The equation for law of energy saving is proved to be transformed to the proper Abel ordinary differential equation.…

### Computing Accurate Age and Distance Factors in Cosmology

- Physics
- 2012

As the universe expands astronomical observables such as brightness and angular size on the sky change in ways that differ from our simple Cartesian expectation. We show how observed quantities…

### An exposition on Friedmann cosmology with negative energy densities

- Physics
- 2015

How would negative energy density affect a classic Friedmann cosmology? Although never measured and possibly unphysical, certain realizations of quantum field theories leaves the door open for such a…

### A Cyclic Cosmological Model Based on the f(ρ) Modified Theory of Gravity

- Physics
- 2011

We consider FLRW cosmological models for perfect fluid (with ρ as the energy density) in the frame work of the f(ρ) modified theory of gravity [V. N. Tunyak, Russ. Phys. J. 21, 1221 (1978); J. R.…

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