A Caltech Library Service

Beyond ΛCDM: Problems, solutions, and the road ahead

Bull, Philip (2016) Beyond ΛCDM: Problems, solutions, and the road ahead. Physics of the Dark Universe, 12 . pp. 56-99. ISSN 2212-6864. doi:10.1016/j.dark.2016.02.001.

[img] PDF - Submitted Version
See Usage Policy.


Use this Persistent URL to link to this item:


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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Alternate Title:Beyond Lambda CDM: Problems, solutions, and the road ahead
Additional Information:© 2016 Elsevier B.V. Received 30 December 2015, Accepted 8 February 2016, Available online 2 March 2016. We are grateful to all of the organizers and participants of the Beyond ΛCDM workshop, held in Oslo, Norway from the 14th–17th January 2015. We would also like to thank A. Linde and M. Maggiore for useful comments. PB is supported by an appointment to the NASA Postdoctoral Program at the Jet Propulsion Laboratory, California Institute of Technology, administered by Oak Ridge Associated Universities through a contract with NASA. PB also acknowledges support from European Research Council grant StG2010-257080. YA acknowledges support from DFG through the project TRR33 “The Dark Universe.” TB is supported by All Souls College, Oxford. EB (Bentivegna) is supported by the project “Digitizing the universe: precision modeling for precision cosmology,” funded by the Italian Ministry of Education, University and Research (MIUR). The work of SC (Clesse) is supported by the Return Grant program of the Belgian Science Policy (BELSPO). FF would like to thank the Kavli Institute for Theoretical Physics China in Beijing, where this contribution was partially written, for hospitality. CL acknowledges support from the Research Council of Norway through grant 216756, and from STFC consolidated grant ST/L00075X/1. RP is supported by the Swedish Research Council, contract number 621-2013-428. The contribution of MSP to this publication was made possible through the support of a grant from the John Templeton Foundation. IDS has been supported by the Fundação para a Ciência e Tecnologia (FCT) through the Investigador research grant SFRH/BPD/95204/2013, as well as UID/FIS/04434/2013. IT acknowledges support from the FCT through the Investigador contract No. IF/01518/2014 and strategic project UID/FIS/04434/2013. FVN is supported by the ERC Starting Grant “cosmoIGM” and partially supported by INFN IS PD51 “INDARK”. The research of MvS leading to these results has received funding from the ERC under the European Community’s Seventh Framework Programme (FP7/2007-2013 Grant no. 307934). Part of the research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
Funding AgencyGrant Number
NASA Postdoctoral ProgramUNSPECIFIED
European Research Council (ERC)StG2010-257080
Deutsche Forschungsgemeinschaft (DFG)TRR33
All Souls College, OxfordUNSPECIFIED
Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR)UNSPECIFIED
Belgian Federal Science Policy Office (BELSPO)UNSPECIFIED
Research Council of Norway216756
Science and Technology Facilities Council (STFC)ST/L00075X/1
Swedish Research Council621-2013-428
John Templeton FoundationUNSPECIFIED
Fundação para a Ciência e Tecnologia (FCT)SFRH/BPD/95204/2013
Fundação para a Ciência e Tecnologia (FCT)UID/FIS/04434/2013
Fundação para a Ciência e Tecnologia (FCT)IF/01518/2014
European Research Council (ERC)cosmoIGM
Istituto Nazionale di Fisica Nucleare (INFN)IS PD51
European Research Council (ERC)307934
Subject Keywords:Cosmology; Dark energy; Cosmological constant problem; Modified gravity; Dark matter; Early universe
Record Number:CaltechAUTHORS:20160603-075120430
Persistent URL:
Official Citation:Philip Bull, Yashar Akrami, Julian Adamek, Tessa Baker, Emilio Bellini, Jose Beltrán Jiménez, Eloisa Bentivegna, Stefano Camera, Sébastien Clesse, Jonathan H. Davis, Enea Di Dio, Jonas Enander, Alan Heavens, Lavinia Heisenberg, Bin Hu, Claudio Llinares, Roy Maartens, Edvard Mörtsell, Seshadri Nadathur, Johannes Noller, Roman Pasechnik, Marcel S. Pawlowski, Thiago S. Pereira, Miguel Quartin, Angelo Ricciardone, Signe Riemer-Sørensen, Massimiliano Rinaldi, Jeremy Sakstein, Ippocratis D. Saltas, Vincenzo Salzano, Ignacy Sawicki, Adam R. Solomon, Douglas Spolyar, Glenn D. Starkman, Danièle Steer, Ismael Tereno, Licia Verde, Francisco Villaescusa-Navarro, Mikael von Strauss, Hans A. Winther, Beyond : Problems, solutions, and the road ahead, Physics of the Dark Universe, Volume 12, June 2016, Pages 56-99, ISSN 2212-6864, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:67635
Deposited By: Tony Diaz
Deposited On:03 Jun 2016 19:10
Last Modified:11 Nov 2021 03:52

Repository Staff Only: item control page