Europhys. Lett.
Volume 74, Number 5, June 2006
Page(s) 930 - 936
Section Geophysics, astronomy, and astrophysics
Published online 03 May 2006
Europhys. Lett., 74 (5), pp. 930-936 (2006)
DOI: 10.1209/epl/i2005-10590-3

On curvature coupling and quintessence fine-tuning

Yungui Gong1, 2, Anzhong Wang2 and Yuan-Zhong Zhang3, 4

1  College of Electronic Engineering, Chongqing University of Posts and Telecommunications - Chongqing 400065, PRC
2  CASPER, Physics Department, Baylor University - Waco, TX 76798, USA
3  CCAST (World Laboratory) - P.O. Box 8730, Beijing 100080, PRC
4  Institute of Theoretical Physics, Chinese Academy of Sciences P.O. Box 2735, Beijing 100080, PRC

received 19 December 2005; accepted in final form 11 April 2006
published online 3 May 2006

We discuss the phenomenological model in which the potential energy of the quintessence field depends linearly on the energy density of the spatial curvature. We find that the pressure of the scalar field takes a different form when the potential of the scalar field also depends on the scale factor and the energy momentum tensor of the scalar field can be expressed as the form of a perfect fluid. A general coupling is proposed to explain the current accelerating expansion of the Universe and solve the fine-tuning problem.

98.80.Cq - Particle-theory and field-theory models of the early Universe (including cosmic pancakes, cosmic strings, chaotic phenomena, inflationary universe, etc.).
98.80.Es - Observational cosmology (including Hubble constant, distance scale, cosmological constant, early Universe, etc.).

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