RT Journal Article
T1 Isotropy theorem for cosmological vector fields
A1 López Maroto, Antonio
A1 Ruiz Cembranos, José Alberto
A1 Nuñez Jareño, Santos José
A1 Hallabrin, C.
AB We consider homogeneous Abelian vector fields in an expanding universe. We find a mechanical analogy in which the system behaves as a particle moving in three dimensions under the action of a central potential. In the case of bounded and rapid evolution compared to the rate of expansion, we show-by making use of the virial theorem-that for an arbitrary potential and polarization pattern, the average energy-momentum tensor is always diagonal and isotropic despite the intrinsic anisotropic evolution of the vector field. For simple power law potentials of the form V = lambda(A(mu)A(mu))(n), the average equation of state is found to be w = (n - 1)/(n + 1). This implies that vector coherent oscillations could act as natural dark matter or dark energy candidates. Finally, we show that under very general conditions, the average energy-momentum tensor of a rapidly evolving bounded vector field in any background geometry is always isotropic and has the perfect fluid form for any locally inertial observer.
PB American Physical Society
SN 1550-7998
YR 2012
FD 2012-07-10
LK https://hdl.handle.net/20.500.14352/44235
UL https://hdl.handle.net/20.500.14352/44235
LA eng
NO © 2012 American Physical Society.This work has been supported by MICINN (Spain) under Project Nos. FIS 2008-01323, FIS2011-23000, FPA2011- 27853 01 and Consolider-Ingenio MULTIDARK under Contract No. CSD2009-00064.
NO MICINN (Spain)
DS Docta Complutense
RD 9 abr 2025