CC BYT. G. ZlosnikJustin I. ReadLicia VerdeGiuseppe VaccaTomi S. KoivistoValerio MarraCarmelita CarboneMarco BaldiFabio FinelliWill J. PercivalValeria PettorinoCamille BonvinJochen WellerLuigi GuzzoRuth DurrerJuan Garcia-BellidoStefano CameraKnud JahnkeLukas HollensteinConstantinos SkordisYun WangMark CropperStephen ApplebyMassimiliano RinaldiRichard MasseyLuca AmendolaNelson J. NunesStefano BorganiDomenico SaponeAlan HeavensFrancesco MontanariRoberto TrottaClaudia de RhamLuciano CasariniCarlos MartinsDida MarkovicDavid J. E. MarshTessa BakerRoberto ScaramellaFederico MarulliNicola BartoloClaudia QuercelliniAnastasios AvgoustidisCarmelita CarboneMarco BaldiValeria PettorinoElisabetta MajerottoEnzo BranchiniLuigi GuzzoClare BurrageLavinia HeisenbergAlain BlanchardShaun A. ThomasCristiano PorcianiIgnacy SawickiConstantinos SkordisYannick MellierThomas D. KitchingAdrian VollmerFergus SimpsonAndy TaylorJ. P. DietrichStefano BorganiEric V. LinderDavid F. MotaZhiqi HwangDavid BaconM. MarchLuciano CasariniRory HolmesHenk HoekstraFilippo VernizziAnne EaletCinzia Di PortoMartin KunzFederico MarulliCatherine HeymansTommaso GiannantonioPedro G. Ferreira2025-06-172025-06-172018-04-122367-36131433-835110.1007/s41114-017-0010-310.48550/arxiv.1606.00180https://ror.circle-u.eu/handle/123456789/814784Euclid is a European Space Agency medium class mission selected for launch in 2020 within the Cosmic Vision 2015 2025 program. The main goal of Euclid is to understand the origin of the accelerated expansion of the universe. Euclid will explore the expansion history of the universe and the evolution of cosmic structures by measuring shapes and redshifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky. Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis. This review has been planned and carried out within Euclid's Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission.OPENCosmology; Dark energy; Galaxy evolution; Physics and Astronomy (miscellaneous)cosmological modelgravitation: modelReview Articlecosmology; dark energy; galaxy evolution; physics and astronomy (miscellaneous)Dark energy; Cosmology; Galaxy evolutionPhysics, Particles & FieldsGALAXY REDSHIFT SURVEYDark energy3-POINT CORRELATION-FUNCTIONCosmology; Dark energy; Galaxy evolution; astro-ph.CO; astro-ph.CO; Physics and Astronomy (miscellaneous)dark energygalaxy: redshiftPhysicsformationCosmology; Dark energy; Galaxy evolutionEQUATION-OF-STATENuclear & Particles Physics520CosmologyPhysical Sciencesastro-ph.COgalaxy: clusterhistoryexpansion: accelerationAstrophysics - Cosmology and Nongalactic AstrophysicsCosmology; Dark energy; Galaxy evolution;Cosmology and Nongalactic Astrophysics (astro-ph.CO)Particles & FieldssatelliteFOS: Physical sciences530dark matterPRIMORDIAL NON-GAUSSIANITYGalaxy evolutionLARGE-SCALE STRUCTUREstructureAtomic physics. Constitution and properties of matterEuclid Theory Working GroupScience & TechnologyDIGITAL-SKY-SURVEYN-BODY SIMULATIONSMICROWAVE-ANISOTROPY-PROBEboundary conditionCOLD DARK-MATTER0201 Astronomical And Space SciencesLENSING MASS RECONSTRUCTION[PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph][PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]QC170-197publication01 natural sciences0103 physical sciences7. Clean energy13. Climate actiondoi_dedup___:8940031c3d4ccc35674334d2df526e0dPMC589788829674941http://arxiv.org/abs/1606.0018011368/294235710852/661282434/57180310281/29229721.11116/0000-0005-CF40-A11572/20754811577/328632311590/34653311567/107120011585/6441281887/6897920.500.11767/1170862318/169323310044/1/60603