DARK ENERGY WITH POLYTROPIC EQUATION-OF-STATE

Equation-of-state parameter plays a significant role for guessing the real nature of dark energy. Here polytropic equation-of-state p = omega rho(n) is chosen for some of the kinematical Lambda-models viz., Lambda similar to ((a)over dot/a)(2), Lambda similar to (a)over dot/a and Lambda similar to rho. Although in dust cases (omega = 0) closed form solutions show no dependency on the polytropic index n, but in non-dust situations some new possibilities are opened up including phantom energy with supernegative (omega < -1) equation-of-state parameter.