Beyond ΛCDM: problems, solutions, and the road ahead
File(s)
Accepted version
OA Location
Author(s)
Type
Journal Article
Abstract
Despite its continued observational successes, there is a persistent (and growing) interest in extending
cosmology beyond the standard model, ΛCDM. This is motivated by a range of apparently serious
theoretical issues, involving such questions as the cosmological constant problem, the particle nature of
dark matter, the validity of general relativity on large scales, the existence of anomalies in the CMB and on
small scales, and the predictivity and testability of the inflationary paradigm. In this paper, we summarize
the current status of ΛCDM as a physical theory, and review investigations into possible alternatives along
a number of different lines, with a particular focus on highlighting the most promising directions. While
the fundamental problems are proving reluctant to yield, the study of alternative cosmologies has led to
considerable progress, with much more to come if hopes about forthcoming high-precision observations
and new theoretical ideas are fulfilled.
cosmology beyond the standard model, ΛCDM. This is motivated by a range of apparently serious
theoretical issues, involving such questions as the cosmological constant problem, the particle nature of
dark matter, the validity of general relativity on large scales, the existence of anomalies in the CMB and on
small scales, and the predictivity and testability of the inflationary paradigm. In this paper, we summarize
the current status of ΛCDM as a physical theory, and review investigations into possible alternatives along
a number of different lines, with a particular focus on highlighting the most promising directions. While
the fundamental problems are proving reluctant to yield, the study of alternative cosmologies has led to
considerable progress, with much more to come if hopes about forthcoming high-precision observations
and new theoretical ideas are fulfilled.
Date Issued
2016-03-02
Date Acceptance
2016-02-08
Citation
Physics of the Dark Universe, 2016, 12, pp.56-99
ISSN
2212-6864
Publisher
Elsevier
Start Page
56
End Page
99
Journal / Book Title
Physics of the Dark Universe
Volume
12
Copyright Statement
© 2016 Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Sponsor
Imperial College Trust
Imperial College Trust
Grant Number
N/A
NA
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
Cosmology
Dark energy
Cosmological constant problem
Modified gravity
Dark matter
Early universe
COLD DARK-MATTER
MICROWAVE-ANISOTROPY-PROBE
FINDER COMPARISON PROJECT
INVERSE-SQUARE LAW
COSMOLOGICAL PARAMETER-ESTIMATION
SMOOTHED PARTICLE HYDRODYNAMICS
BARYON ACOUSTIC-OSCILLATIONS
FINE-STRUCTURE CONSTANT
SCALAR-TENSOR GRAVITY
GALAXY FORMATION
Publication Status
Published