Research co-lead author Professor Baojiu Li, of Durham University's Institute for Computational Cosmology, said: "In General Relativity, scientists account for the accelerated expansion of the universe by introducing a mysterious form of matter called dark energy -- the simplest form of which may be a cosmological constant
, whose density is a constant in space and time.
From these equations, simplified by the cosmological principle for the homogeneous and isotropic universe, Einstein first derived the stationary model universe by introducing a hypothetical cosmological constant
for incorporating Mach's principle.
So he introduced a term, later dubbed the cosmological constant
, which represented an antigravity force that countered the contraction."
In its original formulation the theory had predicted an expanding universe, but sensing that it would go counter to the commonly held belief of a stable and static universe Einstein fudged the equation by introducing a cosmological constant
. But as would happen later in 1929, Mr.
Einstein modified his standard equations by introducing a term to his standard field equations including a constant which is called the cosmological constant
[LAMBDA],  to become
In the simplest case, assume a gravitational function in the form of F(T) = T - 2[[LAMBDA].sub.4], where [[LAMBDA].sub.4] is a positive cosmological constant
. If we define a scalar field [sigma] in the form of [phi] = [[sigma].sup.2][xi], where [xi] = 1/4, by rewriting (6), the effective action is obtained as follows:
The Laplacian is the Laplacian with respect to [g.sub.ij], R is the scalar curvature of the metric, 0 < t is the time coordinate defined by the derivation process of the equation, and [LAMBDA] < 0 a cosmological constant
. If other physical fields had been present in the Einstein equations then the equation would contain further lower order terms (cf.
But it looks like the favorite theory is one that has long been sidelined - that of the cosmological constant
, introduced by Albert Einstein (who else?) over 100 years ago.
We also discuss the cosmological constant
in these spacetimes.
He discusses in detail some of the "key scientific concepts of his career", such as special and general relativity, the 'cosmological constant
', the redshift of spectral lines, unified field theory and quantum mechanics.
Bancoco Host Jason Manford to eliminated "Albert Einstein": "Where did it go wrong for you?" Possibly, Jason, when he needlessly added a cosmological constant
to his theory of relativity to account for a quasi-static distribution of matter as required by the velocity of stars, unaware that the universe was in fact expanding.