Dark energy and cosmological horizon thermal effects

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

Dark Energy and Dark Matter from Cosmological Observations

The introduction of new observational techniques has in the past few years moved cosmology into the era of precision science. With the advent of precision measurements of the cosmic microwave background (CMB), large scale structure (LSS) of galaxies, and distant type Ia supernovae, a new paradigm of cosmology has been established. In this new standard model, the geometry is flat so that Ωtotal ...

Cosmological BCS condensate as dark energy

We argue that the occurrence of late-time acceleration can conveniently be described by first-order general relativity covariantly coupled to fermions. Dark energy arises as a gravitationally driven BCS condensate of fermions which forms in the early universe. At late times, the gap and chemical potential evolve to have an equation of state with effective negative pressure, thus naturally leadi...

Cosmological models with Gurzadyan-Xue dark energy

The formula for dark energy density derived by Gurzadyan and Xue provides a remarkable fit to the SN data, unlike numerous phenomenological dark energy scenarios where the corresponding value is postulated. We consider several cosmological models based on that formula and derive the cosmological equations for each case. It is shown that in all models source terms appear in the continuity equati...