Logarithmic gravity model

The modified $F(R)$ gravity theory with the function $F(R)=-(1/\beta)\ln(1-\beta R)$ is studied. action at small coupling $\beta$ becomes Einstein--Hilbert action. bound on parameter from local tests $\beta\leq 2\times 10^{-6}$ cm$^2$. We find constant curvature solutions and it was shown that de Sitter space unstable but a solution zero Ricci scalar stable. potential mass of field (scalaron) are obtained in Einstein's frame. slow-roll cosmological parameters studied e-folds number evaluated. critical points autonomous equations analyzed. $m(r)$ describes deviation $\Lambda$CDM model calculated.