%0 Journal Article
%T Tunneling in $ĻĢ$ Decaying Cosmologies and the Cosmological Constant Problem
%A M. A. Jafarizadeh
%A F. Darabi
%A A. Rezaei-Aghdam
%A A. R. Rastegar
%J Physics
%D 1998
%I arXiv
%R 10.1103/PhysRevD.60.063514
%X The tunneling rate, with exact prefactor, is calculated to first order in $\hbar$ for an empty closed Friedmann-Robertson-Walker (FRW) universe with decaying cosmological term $\Lambda \sim R^{-m}$ ($R$ is the scale factor and $m$ is a parameter $0\leq m \leq 2$). This model is equivalent to a cosmology with the equation of state $p_{\chi}=(m/3 -1)\rho_{\chi}$. The calculations are performed by applying the dilute-instanton approximation on the corresponding Duru-Kleinert path integral. It is shown that the highest tunneling rate occurs for $m=2$ corresponding to the cosmic string matter universe. The obtained most probable cosmological term, like one obtained by Strominger, accounts for a possible solution to the cosmological constant problem.
%U http://arxiv.org/abs/gr-qc/9811082v2