In cosmology, the equation of state of a perfect fluid is characterized by a dimensionless number w {\displaystyle w} , equal to the ratio of its pressure...

The Friedmann equations, also known as the Friedmann–Lemaître (FL) equations, are a set of equations in physical cosmology that govern cosmic expansion...

chemistry, an equation of state is a thermodynamic equation relating state variables, which describe the state of matter under a given set of physical conditions...

in the general relativity equations. In 1915, Einstein publishes his equations of general relativity, without a cosmological constant Λ. In 1917, Einstein...

theory of relativity, the Einstein field equations (EFE; also known as Einstein's equations) relate the geometry of spacetime to the distribution of matter...

Quantum cosmology is the attempt in theoretical physics to develop a quantum theory of the universe. This approach attempts to answer open questions of classical...

}u^{\alpha }\partial _{\alpha }p} Relativistic heat conduction Equation of state (cosmology) Rezzolla, L. (Luciano) (14 June 2018). Relativistic hydrodynamics...

The Boltzmann equation or Boltzmann transport equation (BTE) describes the statistical behaviour of a thermodynamic system not in a state of equilibrium;...

Friedmann equations: a ( t ) ∝ t 2 / 3 {\displaystyle a(t)\propto t^{2/3}} In physical cosmology, the dark-energy-dominated era is proposed as the last of the...

hole cosmology (also called Schwarzschild cosmology or black hole universe) is a cosmological model in which the observable universe is the interior of a...

Physical cosmology is a branch of cosmology concerned with the study of cosmological models. A cosmological model, or simply cosmology, provides a description...

In cosmology, the steady-state model or steady-state theory was an alternative to the Big Bang theory. In the steady-state model, the density of matter...

In cosmology, recombination refers to the epoch during which charged electrons and protons first became bound to form electrically neutral hydrogen atoms...

cosmology is any physical cosmological model of the universe that was, or still is, proposed as an alternative to the then-current standard model of cosmology...

quintessence. The term was coined by Robert R. Caldwell in 1999. In cosmology, the equation of state of a perfect fluid is given by p = w ρ , {\displaystyle p=w\rho...

density of the dark energy. By definition, an equation of state in cosmology is P = wρc2, and if this is substituted into the fluid equation, which describes...

Einstein's field equations the metric gives the Friedmann equation which has been developed into the Standard Model of modern cosmology, and the further...

region of space). Measuring the equation of state for dark energy is one of the biggest efforts in observational cosmology today. Adding the cosmological constant...

cosmology. Contrary to the general case, the Wheeler–DeWitt equation is well defined in minisuperspaces like the configuration space of cosmological theories...

In physical cosmology, the Big Rip is a hypothetical cosmological model concerning the ultimate fate of the universe, in which the matter of the universe...

Dave, R.; Steinhardt, P. J. (1998). "Cosmological Imprint of an Energy Component with General Equation-of-State". Physical Review Letters. 80 (8): 1582–1585...

different from 1); or quintessence rather than a cosmological constant where the equation of state of dark energy is allowed to differ from −1. Cosmic...

Cosmology (from Ancient Greek κόσμος (cosmos) 'the universe, the world' and λογία (logia) 'study of') is a branch of physics and metaphysics dealing with...

(2008-03-01). "Adventures in Friedmann cosmology: A detailed expansion of the cosmological Friedmann equations". American Journal of Physics. 76 (3): 265–276....

by the cosmological principle and assumed by all models that use the Friedmann–Lemaître–Robertson–Walker metric, including the current version of the ΛCDM...

the values of these cosmological parameters which physicists use to determine the acceleration of the universe. The acceleration equation describes the...

action principle that gives the equations of motion for trace-free Einstein gravity has been proposed, where the cosmological constant emerges as an integration...

Einstein’s theory of special relativity. The notion of a zero-point energy is also important for cosmology, and physics currently lacks a full theoretical...

if there is a positive cosmological constant, as is currently believed). The result is a new solution to Einstein's equations, which Penrose takes to...

In cosmology, decoupling is a period in the development of the universe when different types of particles fall out of thermal equilibrium with each other...