Gravitation and Cosmology

, Volume 17, Issue 4, pp 349–354

On a cosmological invariant as an observational probe in the early universe


DOI: 10.1134/S0202289311040050

Cite this article as:
Gangopadhyay, D. & Mukherjee, S. Gravit. Cosmol. (2011) 17: 349. doi:10.1134/S0202289311040050


k-essence scalar field models are usually taken to have Lagrangians of the form L = −V (φ)F(X) with F some general function of X = ▿μφμϕ. Under certain conditions, this Lagrangian can take the form of that of an oscillator with time-dependent frequency. The Ermakov invariant for a time-dependent oscillator in a cosmological scenario then leads to an invariant quadratic form involving the Hubble parameter and a logarithm of the scale factor. In principle, this invariant can lead to further observational probes for the early Universe. Moreover, if such an invariant can be observationally verified, then the presence of dark energy will also be indirectly confirmed.

Copyright information

© Pleiades Publishing, Ltd. 2011

Authors and Affiliations

  1. 1.S. N. Bose National Centre for Basic SciencesSalt Lake, KolkataIndia
  2. 2.Dharsa Mihirlal Khan Institution [H.S]Dist: HowrahIndia