A Cosmological Model Based on a Quadratic Equation of State Unifying Vacuum Energy, Radiation, and Dark Energy

Figure 7

Evolution of the pressure 𝑝 with the time 𝑡 in linear scales. The dashed line corresponds to the standard radiation model of Section 3.2 exhibiting a finite time singularity at 𝑡=0. Quantum mechanics limits the rise of the pressure to 𝜌_𝑃𝑐²/48=9.66⋅10¹¹⁴g/ms². In the vacuum energy era, the pressure decreases exponentially rapidly, becomes negative, and tends to −𝜌_𝑃𝑐²=−4.64⋅10¹¹⁶g/ms² for 𝑡→−∞.