https://doi.org/10.1140/epjc/s10052-017-4826-5
Regular Article - Theoretical Physics
Phantom dark ghost in Einstein–Cartan gravity
1
Department of Physics, National Taiwan University, Taipei, 10617, Taiwan
2
LeCosPA, National Taiwan University, Taipei, 10617, Taiwan
3
Department of Theoretical Physics, University of the Basque Country UPV/EHU, P.O. Box 644, 48080, Bilbao, Spain
4
IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
5
Graduate Institute of Astrophysics, National Taiwan University, Taipei, 10617, Taiwan
6
Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Stanford University, Stanford, CA, 94305, USA
* e-mail: mariam.bouhmadi@ehu.eus
Received:
23
March
2016
Accepted:
12
April
2017
Published online:
3
May
2017
A class of dynamical dark energy models is constructed through an extended version of fermion fields corresponding to phantom dark ghost spinors, which are spin 1/2 with mass dimension 1. We find that if these spinors interact with torsion fields in a homogeneous and isotropic universe, then it does not imply any future dark energy singularity or any abrupt event, though the fermion has a negative kinetic energy. In fact, the equation of state of this dark energy model will asymptotically approach the value 
from above without crossing the phantom divide and inducing therefore a de Sitter state. Consequently, we expect the model to be stable because no real phantom fields will be created. At late time, the torsion fields will vanish as the corresponding phantom dark ghost spinors dilute. As would be expected, intuitively, this result is unaffected by the presence of cold dark matter although the proof is not as straightforward as in general relativity.
© The Author(s), 2017
