https://doi.org/10.1140/epjc/s10052-019-6876-3
Regular Article - Theoretical Physics
The unphysical character of minimally coupled dark energy fluids
1
Departamento de Matemática e Estatística, Universidade do Estado do Rio Grande do Norte, 59610-210, Mossoró, RN, Brazil
2
Departamento de Física, Universidade do Estado do Rio Grande do Norte, 59610-210, Mossoró, RN, Brazil
3
Grupo de Física Teórica e Física Matemática, Departamento de Física, Universidade Federal Rural do Rio de Janeiro, 23890-971, Seropédica, RJ, Brazil
4
Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330, Juiz de Fora, MG, Brazil
5
Programa de Pós-Graduação Interdisciplinar em Física Aplicada, Instituto de Física, Universidade Federal do Rio de Janeiro, 21941-972, Rio de Janeiro, RJ, Brazil
* e-mail: edesiobarboza@uern.br
Received:
26
November
2018
Accepted:
12
April
2019
Published online:
24
April
2019
It is well known that, in the context of general relativity, an unknown kind of matter that must violate the strong energy condition is required to explain the current accelerated phase of expansion of the Universe. This unknown component is called dark energy and is characterized by an equation of state parameter 
with 
. For minimally coupled dark energy fluids, thermodynamic stability requires that 
and positiveness of entropy that 
. In this paper we proof that we cannot obtain a differentiable function w(a) to represent the dark energy that satisfies these conditions during the entire history of the Universe.
© The Author(s), 2019
