Inflationary cosmology- A new approach using Non-linear electrodynamics

We explore a new kind of field nonlinear electrodynamics(NLED) which acts as source gravity and can accelerate the universe during inflationary era. propose type NLED lagrangian is charecterized by two paremetrs $\alpha$ $\beta$. investigate classical stability causality aspects this model demanding that speed ($C_s = \frac{dP}{d\rho}$) sound wave $C_s^2 > 0$ $C_s \le 1$ find $0 < C_s^2 corresponds to $0.25 \alpha 0.4$ $0.6 \beta B^2 1$. A study deceleration parameter($q \frac{1}{2}(1 + 3 \omega)$, $\omega P/\rho$ being equation state parameter) suggests value $q (i.e. -1/3$ $\ddot{a}(t) ( accelerating universe)) requires $\beta \ge 0.13$. During inflation, energy density $\rho_B$ found be maximum given $\rho_B^{max} 0.65/\beta$ corresponding $\alpha 0.3$. The magnetic necessary trigger $B (= B_{max}) \simeq \sqrt{\frac{0.4 \rho_B^{max}}{0.65}} 4 \times 10^{51}~{\rm Gauss}$, where $\rho_{B}^{max}( =10^{64}~{\rm GeV}^4 $) inflation. also predict e-fold number $N 71$, agrees with experimental result.