Pilgrim dark energy in f ( T ) gravity
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UCLEI, PARTICLES, FIELDS, GRAVITATION, AND ASTROPHYSICS
Pilgrim Dark Energy in f(T) Gravity1 M. Sharif and S. Rani Department of Mathematics, University of the Punjab, Lahore, 54590 Pakistan email: [email protected]; [email protected] Received January 31, 2014
Abstract—We discuss the interacting f(T) gravity with pressureless matter in an FRW spacetime. We con struct an f(T) model by following the correspondence scheme incorporating a recently developed pilgrim dark energy model and taking the Hubble horizon as the IR cutoff. We use constructed model to discuss the evo lution trajectories of the equationofstate parameter, the ωT– ω T' phase plane, and statefinder parameters in the evolving universe. It is found that the equationofstate parameter gives a phantom era of the acceler ated universe for some particular range of the pilgrim parameter. The ωT– ω 'T plane represents freezing regions only for an interacting framework, while the ΛCDM limit is attained in the statefinder plane. We also investigate the first and second laws of thermodynamics assuming equal temperatures at and inside the hori zon in this scenario. Due to the violation of the first law of thermodynamics in f(T) gravity, we explore the behavior of the entropy production term. The validity of a generalized second law of thermodynamics depends on the presentday value of the Hubble parameter. DOI: 10.1134/S1063776114070152 1
1. INTRODUCTION
nostics in a specific f(T) model [6], validity/violation of the first and second laws of thermodynamics using the Wald entropy, correctedentropy versions and magnetic field scenarios [7–9], and many more.
There is increasing evidence of dark energy (DE) over the last few years, which is assumed to be respon sible for the accelerated expansion of the universe. This has been confirmed by a variety of observational constraints in the framework of different observational schemes [1]. The standard cosmology has been remarkably successful, but there remain some serious unresolved issues including the search for the best DE candidate. The origin and nature of DE is still unknown except in some particular ranges of the equa tionofstate (EoS) parameter ω. In the absence of any solid argument in favor of a DE candidate, various approaches have been adopted such as dynamical DE models, and modified and higherdimensional gravi ties.
The search for a viable DE model is the basic key leading to the reconstruction phenomenon, particu larly in modified theories of gravity. The correspond ing energy densities are compared to construct the modified function in the underlying gravity. In this manner, the family of holographic reconstruction of DE models attains a significant place in discussing the accelerated expansion of the universe. Different f(T) models were reconstructed via holographic DE (HDE) and new agegraphic DE (original and entropy corrected) models in [10]. The authors concluded that the corresponding EoS parameter gives consistent results in entropycorrected models. In [11], a
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