Regular Article - Theoretical Physics
Stability of curvature perturbation with new covariant form for energy-momentum transfer in dark sector
Institute of Modern Physics, Northwest University, Xian, 710069, P.R. China
2 Faculty of Science, Ningbo University, Ningbo, 315211, P.R. China
Published online: 28 February 2013
It was found that the model with interaction between cold dark matter (CDM) and dark energy (DE) proportional to the energy density of CDM ρ m and constant equation of state of DE w d suffered from instabilities of the density perturbations on the super-Hubble scales. Here we suggest a new covariant model for the energy-momentum transfer between CDM and DE. Then using the covariant model, we analyze the evolution of density perturbations on the super-Hubble scale. We find that the instabilities can be avoided in the model with constant w d and interaction proportional to ρ m . Furthermore, we analyze the dominant non-adiabatic mode in the radiation era and find that the mode grows regularly.
© Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica, 2013