Dark energy dominance and cosmic acceleration in first-order formalism
- Dipartimento di Matematica, Universita di Torino, Via C. Alberto 10, 10123 Torino (Italy)
- Institute of Theoretical Physics, University of Wroclaw, Pl. Maksa Borna 9, 50-204 Wroclaw (Poland)
- Inst. Catalana de Recerca i Estudis Avancats (ICREA), Barcelona and Inst. d'Estudis Espacials de Catalunya (IEEC)/ICE CSIC, Campus UAB, Fac. Ciencias, Torre C5-Par-2a E-08193 Bellaterra, Barcelona (Spain)
The current accelerated universe could be produced by modified gravitational dynamics as it can be seen, in particular, in its Palatini formulation. We analyze here a specific nonlinear gravity-scalar system in the first-order Palatini formalism which leads to a Friedmann-Robertson-Walker cosmology different from the purely metric one. It is shown that the emerging Friedmann-Robertson-Walker cosmology may lead either to an effective quintessence phase (cosmic speed-up) or to an effective phantom phase. Moreover, the already known gravity assisted dark energy dominance occurs also in the first-order formalism. Finally, it is shown that a dynamical theory able to resolve the cosmological constant problem exists also in this formalism, in close parallel with the standard metric formulation.
- OSTI ID:
- 20713522
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 72, Issue 6; Other Information: DOI: 10.1103/PhysRevD.72.063505; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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