The Cosmological Constant Problems (Talk given at Dark Matter 2000, February, 2000)

Abstract

The old cosmological constant problem is to understand why the vacuum energy is so small; the new problem is to understand why it is comparable to the present mass density. Several approaches to these problems are reviewed. Quintessence does not help with either; anthropic considerations offer a possibility of solving both. In theories with a scalar field that takes random initial values, the anthropic principle may apply to the cosmological constant, but probably to nothing else.

10 pages, Latex

Cited by in corpus (46)

• Beyond the Cosmological Standard Model
• A Dark Energy Model Characterized by the Age of the Universe
• The Casimir effect: Recent controversies and progress
• The Effective Field Theorist's Approach to Gravitational Dynamics
• Low Energy Supersymmetry From the Landscape
• Notes on Ghost Dark Energy
• More on QCD Ghost Dark Energy
• A Conical Tear Drop as a Vacuum-Energy Drain for the Solution of the Cosmological Constant Problem
• Natural Quintessence and Large Extra Dimensions
• Branches of the Landscape
• Mimicking Lambda with a spin-two ghost condensate
• Alleviation of Cosmic Age Problem In Interacting Dark Energy Model
• Accelerating Universes and String Theory
• The Cosmological Constant and Horava-Lifshitz Gravity
• The Cosmic Microwave Background for a Nearly Flat Compact Hyperbolic Universe
• Lorentz invariance and the zero-point stress-energy tensor
• New Agegraphic Dark Energy in Brans-Dicke Theory
• Bayesian Comparison of Interacting Scenarios
• Status on bidimensional dark energy parameterizations using SNe Ia JLA and BAO datasets
• Testing $\Lambda$CDM cosmology in a binned universe: anomalies in the deceleration parameter
• Vacuum fluctuations in a supersymmetric model in FRW spacetime
• TDiff and Weyl Invariant Massive Spin-2: Linear Theory
• The impact of dark energy on galaxy formation. What does the future of our Universe hold?
• A Comment or two on Holographic Dark Energy
• Theoretical Limits on Agegraphic Quintessence from Weak Gravity Conjecture
• Vacuum fluctuations of the supersymmetric field in curved background
• Unification of Inflation and Dark Energy from Spontaneous Breaking of Scale Invariance
• Transient acceleration in $f(T)$ gravity
• Testing dark energy models with $H(z)$ data
• Joint Analysis of Constraints on f(R) Parametrization from Recent Cosmological Observations
• Brane Universes and the Cosmological Constant
• Cosmological constant: relaxation vs multiverse
• Cosmological evolution in Weyl conformal geometry
• Flat-brane Compactifications in Supergravity Induced by Scalars
• Evolving extrinsic curvature and the cosmological constant problem
• Diagnosing the cosmic coincidence problem and its evolution with recent observations
• Local Unit Invariance, Back-Reacting Tractors and the Cosmological Constant Problem
• Noether symmetry approach in non-minimal derivative coupling gravity
• Evidence against Ryskin's model of cosmic acceleration
• The Cosmological Constant Problem from the Point of View of String Theory
• Dynamically tuning away the cosmological constant in effective scalar tensor theories
• Unbroken discrete supersymmetry
• Installing of cosmological constant
• Noether Supercurrents, Supergravity and Broken Supersymmetry
• The Friedman Universe with the stochastic cosmological constant
• Universe Decay, Inflation and the Large Eigenvalue of the Cosmological Constant Seesaw