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Indexed by:期刊论文

Date of Publication:2021-01-10

Journal:JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS

Issue:10

ISSN No.:1475-7516

Key Words:inflation; modified gravity

Abstract:The general Poincare gauge cosmology given by a nine-parameter parity-conserving gravitational Lagrangian with ghost- and tachyon-free conditions is studied from the perspective of field theory. By introducing new variables for replacing two (pseudo-) scalar torsions, the Poincare gauge cosmological system can be recast into a gravitational system coupled to two-scalar fields with a potential up to quartic-order. We discussed the possibility of this system producing inflation without any extra inflatons. The numerical analysis shows that the two-scalar fields system evolved in a potential well processes spontaneously four stages: "pre-inflation", slow-roll inflation with large enough e-folds, "pre-reheating" and reheating. We also studied the stableness of this system by setting large values of initial kinetic energies. The results show that even if the system evolves past the highest point of the potential well, the scalar fields can still return to the potential well and cause inflation. The Poincare gauge cosmology provides us with a self-consistent candidate for inflation.