Fermionic wave functions and Grassmann fields as possible sources of dark energy

• Autor(a) principal: Brito, L. C. T.
• Data de Publicação: 2022
• Outros Autores: Pereira, S. H. [UNESP], Barboza, L. N., Felipe, J. C. C., Jesus, J. F. [UNESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1140/epjc/s10052-022-10779-y; http://hdl.handle.net/11449/237875

We study a cosmological model with a fermionic field which can be interpreted as a source of dark energy in the universe. Two different approaches were considered, the first one with a massless fermionic field represented by a standard wave-function and the second one where a massive field is a Grassmann variable. The first case naturally reduces to a XCDM model with a constant equation of state parameter, while the last case reproduces a w(z)CDM model for a massive field, and in the massless limit, the intrinsic Grassmannian property of the field leads always to a vacuum equation of state parameter, irrespective the specific form of the potential. Both cases leads to a dark energy contribution of the fermionic sector. The models are totally compatible with recent cosmological data from Supernovae, BAO and Hubble parameter measurements. A brief study of linear evolution of density perturbations shows that some of the small scale problems related to standard model can be at least alleviated.