Cosmological evolution with quadratic gravity and nonideal fluids

Abstract Some cosmological models based on the gravitational theory $$f(R)=R+\zeta R^2$$ f ( R ) = + ζ 2 , and fluids obeying to equations of state Redlich–Kwong, Berthelot, Dieterici are proposed for describing smooth transitions between different cosmic epochs. A dynamical system analysis reveals that these contain fixed points which correspond an inflationary, a radiation dominated late-time accelerating epoch, nonsingular bouncing solution, latter being asymptotic point compactified phase space. The infinity space is interpreted as region in non-ideal behaviors previously mentioned suppressed. Physical constraints adopted dimensionless variables derived by demanding be free from ghost tachyonic instabilities, novel interpretation such through cosmographic analysis. effects equation parameters number equilibrium solutions their stability nature clarified. generic properties models, not sensitive particular fluid considered, identified, while differences critically examined showing Redlich–Kwong scenario admits second radiation-dominated epoch Big Rip Singularity.