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Title: f(T,T) gravity and cosmology

We present an extension of f(T) gravity, allowing for a general coupling of the torsion scalar T with the trace of the matter energy-momentum tensor T. The resulting f(T,T) theory is a new modified gravity, since it is different from all the existing torsion or curvature based constructions. Applied to a cosmological framework, it leads to interesting phenomenology. In particular, one can obtain a unified description of the initial inflationary phase, the subsequent non-accelerating, matter-dominated expansion, and then the transition to a late-time accelerating phase. Additionally, the effective dark energy sector can be quintessence or phantom-like, or exhibit the phantom-divide crossing during the evolution. Moreover, in the far future the universe results either to a de Sitter exponential expansion, or to eternal power-law accelerated expansions. Finally, a detailed study of the scalar perturbations at the linear level reveals that f(T,T) cosmology can be free of ghosts and instabilities for a wide class of ansatzes and model parameters.
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Department of Mathematics, University College London, Gower Street, London WC1E 6BT (United Kingdom)
  2. Centro de Astronomia e Astrofísica da Universidade de Lisboa, Campo Grande, Edificío C8, 1749-016 Lisboa (Portugal)
  3. Departamento de Física, ICE, Universidade Federal de Juiz de Fora, Caixa Postal 36036-330, Minas Gerais (Brazil)
  4. Physics Division, National Technical University of Athens, 15780 Zografou Campus, Athens (Greece)
Publication Date:
OSTI Identifier:
22382074
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 12; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMOLOGY; COUPLING; DE SITTER GROUP; DE SITTER SPACE; ENERGY-MOMENTUM TENSOR; EXPANSION; GRAVITATION; NONLUMINOUS MATTER; PERTURBATION THEORY; SCALARS; TORSION; UNIVERSE