Dark Energy and Cosmological Constant

The Cosmological Constant and Dark Energy

Physics invites the idea that space contains energy whose gravitational effect approximates that of Einstein’s cosmological constant, Λ; nowadays the concept is termed dark energy or quintessence. Physics also suggests the dark energy could be dynamical, allowing the arguably appealing picture that the dark energy density is evolving to its natural value, zero, and is small now because the expa...

Cosmological Constant and Dark Energy: Historical Insights

The Hubble Constant and Dark Energy from Cosmological Distance Measures

We study how the determination of the Hubble constant from cosmological distance measures is affected by models of dark energy and vice versa. For this purpose, constraints on the Hubble constant and dark energy are investigated using the cosmological observations of cosmic microwave background, baryon acoustic oscillations and type Ia suprenovae. When one investigates dark energy, the Hubble c...

Dark energy, a cosmological constant, and type Ia supernovae

We focus on uncertainties in supernova measurements, in particular of individual magnitudes and redshifts, to review to what extent supernovae measurements of the expansion history of the universe are likely to allow us to constrain a possibly redshift-dependent equation of state of dark energy, w(z). We focus in particular on the central question of how well one might rule out the possibility ...

Lemaître Class Dark Energy Model for Relaxing Cosmological Constant

Cosmological constant corresponds to the maximally symmetric cosmological term with the equation of state p = −ρ. Introducing a cosmological term with the reduced symmetry, pr = −ρ in the spherically symmetric case, makes cosmological constant intrinsically variable component of a variable cosmological term which describes time-dependent and spatially inhomogeneous vacuum dark energy. Relaxatio...