Cosmological constant—the weight of the vacuum

  title={Cosmological constant—the weight of the vacuum},
  author={Thanu Padmanabhan},
  journal={Physics Reports},

Analytical considerations about the cosmological constant and dark energy

The accelerated expansion of the universe has now been confirmed by several independent observations including those of high redshift type Ia supernovae, and the cosmic microwave background combined

The Cosmological Constant Problem and Running Vacuum in the Expanding Universe

. It is well-known that quantum field theory (QFT) induces a huge value of the cosmological constant, Λ, which is outrageously inconsistent with cosmological observations. We review here some aspects

The Cosmological constant problem

Observational evidence seems to indicate that the expansion of the universe is currently accelerating. Such an acceleration strongly suggests that the content of the universe is dominated by a

Dark energy and gravity

I review the problem of dark energy focussing on cosmological constant as the candidate and discuss what it tells us regarding the nature of gravity. Section 1 briefly overviews the currently popular

Evolution of the cosmological constant in effective gravity

In contrast to the phenomenon of nullification of the cosmological constant in equilibrium vacuum, which is the general property of any quantum vacuum, there are many options in modifying the

The cosmological constant problem and running vacuum in the expanding universe

It is well known that quantum field theory (QFT) induces a huge value of the cosmological constant (CC), Λ, which is outrageously inconsistent with cosmological observations. We review here some

Cosmological constant and vacuum energy: old and new ideas

The cosmological constant (CC) term in Einstein's equations, Λ, was first associated to the idea of vacuum energy density. Notwithstanding, it is well-known that there is a huge, in fact appalling,

Cosmological Constant from the Emergent Gravity Perspective

Observations indicate that our universe is characterized by a late-time accelerating phase, possibly driven by a cosmological constant $\Lambda$, with the dimensionless parameter $\Lambda L_P^2

Finite temperature contributions to cosmological constant

  • I. Park
  • Physics
    International Journal of Modern Physics A
  • 2022
We reexamine the cosmological constant problem in a finite temperature setup and propose an intriguing possibility of carrying out perturbative analysis by employing a renormalization scheme in which

Cosmological implications and structure formation from a time varying vacuum

ABSTRACT We study the dynamics of the FLRW flat cosmological models in which thevacuum energy varies with time, Λ(t). In this model we find that the maincosmological functions such as the scale factor



The observational case for a low-density Universe with a non-zero cosmological constant

OBSERVATIONS are providing progressively tighter constraints on cosmological models advanced to explain the formation of large-scale structure in the Universe. These include recent determinations of

The cosmological constant and cold dark matter

THE cold dark matter (CDM) model1–4 for the formation and distribution of galaxies in a universe with exactly the critical density is theoretically appealing and has proved to be durable, but recent

Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant

We present spectral and photometric observations of 10 Type Ia supernovae (SNe Ia) in the redshift range 0.16 ≤ z ≤ 0.62. The luminosity distances of these objects are determined by methods that

Standard Cosmology and Alternatives: A Critical Appraisal

▪ Abstract This review takes a critical look at the cosmological scenario at the turn of the century by examining the available cosmological models in the light of the present observational evidence.

Old Galaxies at High Redshift and the Cosmological Constant

In a recent striking discovery, Dunlop et al. (1996) observed a galaxy at redshift z = 1.55 with an estimated age of 3.5 Gyr. This is incompatible with age estimates for a flat matter-dominated

The Cosmological Constant and Dark Energy

Physics invites the idea that space contains energy whose gravitational effect approximates that of Einstein's cosmological constant, Lambda: nowadays the concept is termed dark energy or

Cosmological consequences of a rolling homogeneous scalar field.

  • RatraPeebles
  • Physics
    Physical review. D, Particles and fields
  • 1988
It is argued that a number of models in which the energy density of the scalar field red-shifts in a specific manner are studied could reconcile the low dynamical estimates of the mean mass density with the negligibly small spatial curvature preferred by inflation.

Why the Universe is Just So

Some properties of the world are fixed by physics derived from mathematical symmetries, while others are selected from an ensemble of possibilities. Several successes and failures of ‘‘anthropic’’